Check Validity and Fraud Prevention: Complete 2025 Guide

Check Fraud Statistics: The Current Reality

Check fraud is not a declining problem. Despite the growth of electronic payments, check fraud has increased substantially in recent years, driven primarily by mail theft check fraud and the availability of inexpensive photo editing software that makes counterfeiting easier than ever before.

According to FBI check fraud data from the FBI and the US Postal Inspection Service, Suspicious Activity Reports related to check fraud nearly doubled from 2021 to 2023. The increase was directly linked to a surge in mail theft from USPS collection boxes, postal facilities, and delivery routes. Fraudsters steal legitimate checks from the mail, then either wash them to alter the payee and amount or cook them digitally to print multiple copies from a single stolen check image.

The Federal Reserve identified check alteration and counterfeiting as among the most common types of check fraud facing businesses and consumers. The Georgia Department of Banking and Finance noted that affordable desktop publishing software and high-quality color printers have made it easier than ever to create convincing counterfeit checks. What once required specialized equipment now requires only a consumer-grade printer and a photo editing application.

The practical implication for both consumers and businesses is that treating any received check with a basic verification discipline is no longer optional for significant transactions. Understanding what a valid check looks like, what signs indicate fraud, and what to do when something looks wrong is essential financial literacy in the current environment.

What Legally Makes a Check Valid

For a personal or business check to be a valid negotiable instrument under US commercial law, it must contain several required elements. Missing or incorrect elements can cause a check to be rejected by the bank, returned unpaid, or deemed invalid regardless of the signer's intent.

Required Elements on Every Check

The payee name. The line starting with "Pay to the order of" must name a specific payee: a person's name, a business name, or the word "cash." A blank payee line is a significant security risk because it makes the check payable to anyone who holds it, but it is technically processable at some institutions. Most businesses that accept checks should refuse any check with a blank payee line.

The dollar amount in both figures and words. The numeric amount in the box and the written amount on the line must match. When they conflict, the written-out amount controls under most US state laws following the UCC. A check where these two amounts differ is technically processable but may be flagged or returned by the bank.

The date. The date field is required, though a check without a date may still be processed by some banks. Post-dated checks (dated in the future) are a separate issue covered below.

The authorized signature. The maker (the person or entity the account belongs to) must sign the check in the designated signature field. An unsigned check is not negotiable. A forged signature creates a fraudulent instrument even if all other elements are correct.

The MICR line (MICR line verification). The Magnetic Ink Character Recognition line at the bottom of every check carries the routing number, account number, and check number in magnetic ink. This is not a written element but it must be present and correct. A check without a MICR line will not process through the banking system and is effectively invalid for deposit or cashing.

Drawn on a real account at a real financial institution. The routing number must match a real, active US financial institution in the Federal Reserve routing directory (E-Payments Routing Directory). The account number must correspond to a real account at that institution. A check drawn on a nonexistent bank or a closed account is invalid regardless of how complete it appears.

What Legally Makes a Check Invalid

Several circumstances make a check invalid even if it appears complete and properly filled out.

Post-Dated Checks

A post-dated check bears a date in the future. Legally, the account holder is instructing the bank not to process the check until that date. In practice, many banks process checks on the date they are deposited regardless of the written date, especially if the account holder has not separately notified the bank of the post-dated check and requested a hold. A post-dated check deposited before its written date may clear (if funds are available) or bounce (if the account holder timed it intentionally). Never accept a post-dated check as guaranteed future payment without understanding your bank's policy on honoring the date.

Stale-Dated Checks

A stale check (stale-dated check) is one that is six months or more past its written date. Most banks are not required to honor checks older than six months, though they may do so at their discretion. If you receive a check and cannot deposit it immediately, do so before the six-month window closes. Business checks and government checks may have shorter validity periods printed directly on the check face: "Void after 90 days" is common on payroll and vendor checks.

Stop Payment Orders

If the account holder contacts their bank and places a stop payment order on a specific check, the bank will refuse to process that check when it is presented for deposit or cashing. A stop payment does not cancel the underlying debt obligation, but it makes the specific check instrument invalid for processing. Stop payments typically cost a fee and expire after a defined period unless renewed.

Altered Checks

A check that has been materially altered after the authorized signer signed it is invalid. The original issuer is typically not liable for the altered amount under UCC provisions, though the rules on who bears the loss for altered checks depend on which party was negligent and what security measures were or were not in place.

Insufficient Funds

A check drawn on an account with insufficient funds (NSF) that bounces is called a bounced check. Check kiting, which involves moving funds between accounts to inflate apparent balances, is a related fraud type. at the time of processing will be returned unpaid and marked NSF. This is technically a check that bounced, not an invalid check in the legal sense, though the practical effect is the same: no funds transfer. The account holder may face NSF fees from their bank. Some states treat writing checks on accounts with known insufficient funds as a criminal act.

Forged Signatures

A check signed by someone other than an authorized account holder without authorization is fraudulently endorsed and invalid. The bank is generally liable for honoring a forged signature check if it failed to exercise reasonable care in the verification process, though the rules depend on the facts of each case and applicable state law.

How to Verify a Check You Receive

The check verification process involves confirming that a check you have received is legitimate, that it is drawn on a real account, and that it is likely to clear. For routine, low-value checks from trusted sources, full verification may be unnecessary. For any check of significant value from an unfamiliar party, verification should be a fixed step before depositing.

Step 1: Physical Inspection

Before anything else, examine the physical check carefully. A counterfeit check often reveals itself on visual and tactile inspection. Hold the check up to light and look for a watermark. Run your fingertip across the MICR line at the bottom: the MICR magnetic ink should feel flat and dull, not raised or shiny. Check the edges: at least one edge of a legitimate check torn from a book should feel rough or perforated. All four smooth edges suggests the check was printed on plain paper rather than torn from a genuine check book. Feel the paper: matte check paper has a specific texture and is the correct standard. Glossy check paper is a red flag.

Step 2: Verify the Bank

Begin routing number verification: confirm the bank name on the check corresponds to a real financial institution. The FDIC BankFind tool at fdic.gov lets you verify any US bank is real and insured. Look up the bank's routing number in the Federal Reserve's E-Payments Routing Directory (freely accessible online) to confirm the institution is real and active. Compare the routing number printed on the check to the ABA routing number for the named bank in your state. A mismatch between the bank name and the routing number is a strong indicator of a counterfeit check.

If you need to call the bank to verify the check, use the phone number from the bank's official website, not the phone number printed on the check. A fraudster who prints a fake check (and forges the check endorsement or payee) can also print a fake phone number that leads to a confederate who confirms the check's validity.

Step 3: Verify the Check Number

Every legitimate check has the same check number printed in two places: the upper right corner of the check face and at the end of the MICR line at the bottom. If these two numbers do not match, the check is fraudulent. This mismatch is one of the clearest and fastest indicators of counterfeiting because it is easy to spot and difficult to fake consistently.

Step 4: Check for Security Features

ABA-compliant checks produced on security paper include visible and testable security features. Look for a microprinting line along the signature area (it looks like a thin rule but resolves as text under a loupe). Look for the CPSA padlock icon or a printed security features list along one edge of the check. Rub your finger across the thermochromic ink element (often a padlock, a temperature icon, or the word "ORIGINAL") and confirm it disappears when warmed and returns when released. A check that lacks these features may be a counterfeit printed on plain stock.

Step 5: Call the Issuing Bank to Verify the Account

For checks of significant value, call the issuing bank using a number from its official website and ask the bank to verify that the account number is real and that the check number matches an issued instrument. Note that a bank can confirm whether an account exists but typically cannot tell you whether funds are available at that specific moment, since balances change constantly and a fraudster can manipulate account balances temporarily.

Fake Check Signs: Physical Indicators of a Counterfeit Check

The Federal Reserve, FBI, and Georgia Department of Banking and Finance have all published check fraud detection guidance identifying the most reliable physical indicators. This is the complete list:

• MICR line is raised or shiny. Genuine magnetic ink is flat and dull. Counterfeit checks printed on office printers use toner or regular ink that appears raised or reflects light under close inspection.

• All four edges are smooth. Legitimate personal and business checks are torn or cut from a book with at least one perforated edge. A check where all four edges are perfectly smooth is almost always printed, not torn from a genuine check book.

• The paper is thin, glossy, or slippery. ABA-compliant check paper has a specific matte finish and heft. Office printer paper, even cardstock, does not replicate the feel of security check paper.

• Ink smears when dampened (ink test). An ink test is simple: Genuine check printing uses high-quality indelible ink that does not smear when slightly moistened. A brief, careful water test on a corner of the check face reveals counterfeit ink that runs or smears.

• No watermark when held to light. ABA-compliant checks contain a genuine paper watermark embedded in the fiber during manufacturing. No watermark visible when the check is held against a light source suggests plain paper rather than security stock.

• Check number mismatch. The check number in the upper right corner and the check number at the end of the MICR line must match exactly. A mismatch confirms fraud.

• Font inconsistencies. On a legitimate check, all printed text uses consistent fonts, sizes, and capitalization. Counterfeits often show font changes between different fields, particularly between the date or memo line and the payee or amount, because different sections were edited at different times.

• Spelling errors or typos. Banks and professional check manufacturers do not have typos in bank names, addresses, or standard text. Spelling errors on any printed element are strong fraud indicators.

• Missing or incorrect bank logo or address. A check without a bank logo, with a logo that does not match the bank's current branding, or with a bank address that does not correspond to a real branch location is suspicious.

• Back of check is blank or generic. Many security check programs print security warnings, safety features lists, or bank branding on the check back. A completely blank or very plain check back may indicate the check was not produced by a professional manufacturer.

• Erasure marks, dried liquid marks, or color inconsistencies. Any area of the check that appears lighter, darker, or of a slightly different shade than surrounding areas may indicate washing or physical alteration. Holding the check at an angle under a light source often reveals these variations.
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What Is Check Washing and How It Works

Check washing is a physical fraud technique. The fraudster obtains a legitimate check through mail theft or other means, then applies household chemicals to the check's surface to dissolve the ink in the payee name and amount fields while leaving the routing number, account number, and authorized signature intact. After the original ink is removed, the fraudster rewrites the payee name (usually their own name or an alias) and writes a significantly larger dollar amount, then deposits or cashes the altered check.

The chemicals commonly used in check washing include acetone (found in nail polish remover), bleach, and various industrial solvents. These substances dissolve the dye-based inks typically used in consumer pens and some printers. The process takes only minutes when the right chemicals are applied in the right concentration to a check printed in vulnerable ink.

The prevention against check washing operates at two levels. The check paper level: ABA-compliant chemically reactive security paper treats the paper itself during manufacturing so that any washing solvent application produces a visible stain or color change. This cannot be concealed or reversed. A bank teller or automated processing system that examines a washed ABA-compliant check will see permanent evidence of the chemical attack even if the fraudster has rewritten the fields.

The writing instrument level: the FBI recommends writing checks with gel ink pens rather than ballpoint pens. Gel ink penetrates deeper into the paper fiber than ballpoint or felt-tip ink, making it significantly harder to wash without visibly damaging the paper. Writing checks in black gel ink is the single most effective individual behavior-based defense against check washing for any check writer.

The FBI also recommends that individuals mail checks directly inside post office lobbies rather than in street collection boxes, which are primary targets for check thieves. A significant portion of the check fraud increase since 2021 traces directly to mail theft from blue collection boxes.

What Is Check Cooking and Why It Is Growing

Check cooking is digital check fraud (check cooking digital fraud), and the FBI specifically identified it as a growing method in its 2025 alert on mail theft-related check fraud. Unlike check washing, which alters the physical document, check cooking creates entirely new fraudulent checks from a digital image of a stolen original.

The process: a criminal steals a check from the mail or obtains a check image through other means, photographs or scans it to create a digital file, opens it in a standard photo editing application, alters the payee name and amount, and then prints multiple copies on a consumer-grade printer. From a single stolen check, a fraudster can produce dozens of fraudulent checks, often written for amounts just below the thresholds that trigger enhanced bank scrutiny.

This method is particularly dangerous because the printed copies contain legitimate routing numbers, account numbers, and authorized signatures from the original. The only detectable difference from a legitimate check is that the copies are not printed on ABA-compliant security paper.

ABA security paper features stop cooked checks through two mechanisms. The void pantograph embedded in the check background of a genuine check produces a visible VOID pattern when the check is scanned or photocopied because the pantograph's line density renders differently through imaging equipment than it does to the naked eye. A cooked check copied from a scanned original will either show the VOID pattern visibly in the digital image or will lack the pantograph entirely (if the fraudster edits it out), either of which is a detectable difference from a genuine check.

UV fluorescent fibers embedded in ABA-compliant security paper are the second detection mechanism. A genuine check viewed under UV light shows a distinctive fiber glow pattern distributed through the paper. A cooked check printed on plain paper does not. Bank counter UV verification lights can identify cooked checks in seconds using this test alone.

Check Alteration: Changing What Is Already Written

Check alteration differs from counterfeiting and cooking. An altered check is a legitimate check that has been physically modified after it was issued. The Federal Reserve defines alteration as an unauthorized change that modifies the obligation of a party: changing the payee name, changing the amount, or changing the date.

Common alteration methods include washing (covered above), physically erasing pencil-written amounts (less common since most checks are ink-written), and carefully overwriting ink with matching ink using art pens or calligraphy tools.

The indicators of alteration are different from counterfeiting indicators. Look for areas of the check that appear slightly different in color, tone, or texture from surrounding areas. Under certain lighting angles, washed areas reflect light differently from unaltered paper. Altered check amounts often show slight misalignment between the handwritten digits because they were added by a different person under different writing conditions than the original.

For the account holder who issued a check that is later altered: US commercial law generally places liability for altered checks on the party whose negligence allowed the alteration. Writing checks on ABA-compliant security paper, using indelible gel ink, filling in all fields completely (leaving no blank space in the amount or payee lines), and drawing a line through any remaining blank space in the written amount line all reduce alteration risk.

The Overpayment Scam: How It Catches People Out

The overpayment scam is consistently among the most effective and damaging check fraud schemes targeting individuals. The FTC and Consumer Financial Protection Bureau both include it in their top fraud warnings.

The pattern: someone sends you a check for more than an agreed-upon amount (a purchase of something you are selling, a freelance payment, a rental deposit) and asks you to deposit the check and wire or send back the difference. The check appears genuine and your bank makes the funds available quickly due to Regulation CC hold time requirements. You send the difference. Days later, the bank determines the check is fraudulent and removes the funds from your account. You are now out both the wired-back funds and the original amount the check was supposed to cover.

The critical point that makes this scam work is the timing difference between funds availability and check clearing. Regulation CC requires banks to make check funds available within specified hold periods, typically one to two business days for most checks. But the process of verifying that a check is actually paid by the issuing bank can take several days to weeks. A fraudulent check can appear to have cleared before the fraud is detected. The funds you see in your account during that window are not yet confirmed; they are provisional.

Never send money back from a check, through any channel, to someone you do not know personally, regardless of how the check appears or how convincingly the story is presented. No legitimate transaction requires you to receive a check for more than the agreed amount and wire back the difference. If a check is overpaying you and someone wants the excess returned, return the entire check uncashed and ask for a correct-amount check.

How to Protect Checks You Write

Check fraud victimizes both check recipients (who receive fraudulent checks) and check writers (whose checks are stolen and altered or whose account information is used to create counterfeits). Protecting the checks you write requires attention to several specific practices.

Use Gel Ink Pens

Write all checks with black or blue gel ink pens rather than ballpoint, felt-tip, or rollerball pens. Gel ink penetrates deeper into paper fibers than other ink types, making chemical washing significantly harder. The FBI specifically recommends gel ink pens as a check washing prevention measure. Keep a dedicated gel pen with your checkbook and replace it before it runs low to avoid pressure-inconsistent writing that leaves vulnerable areas.

Fill Out All Fields Completely

Leave no blank spaces in any field on any check. Write the payee name immediately after "Pay to the order of" with no gap before the name that a fraudster could use to insert additional characters. Draw a line through any remaining blank space in the written amount line after writing the amount. Write the amount in words as closely as possible to where "Dollars" is printed, leaving no space for a fraudster to insert additional words that increase the amount.

Mail Checks Securely

Take checks directly to a post office counter rather than depositing them in a street collection box or an apartment building mail area. The FBI's check fraud alert specifically identified blue street collection boxes as primary targets for mail thieves. If mailing checks is unavoidable outside of direct post office submission, consider using security envelopes that make the check contents less visible, and use tracked mailing options for any high-value check.

Use Check Positive Pay for Business Accounts

Positive pay is a business banking service where you upload a file of all issued checks (check numbers, amounts, and payee names) to your bank. When checks present for payment, the bank matches them against your issued check file and flags any check that does not match. This is the most effective automated defense against counterfeit and altered check fraud for businesses with regular check volume. Many banks offer positive pay at no additional cost for business checking accounts.

Order Checks on ABA-Compliant Security Paper

Order your personal and business checks from a CPSA-certified manufacturer who produces checks on ABA-compliant, ABA compliant security stock. Checks printed on security paper resist washing through the chemically reactive paper feature, resist counterfeiting through void pantograph and UV fiber features, and resist physical alteration through the security background pattern. A check on ABA security paper is fundamentally harder to wash, cook, or counterfeit convincingly than a check on plain stock.

Checkomatic's personal checks and business checks ship on ABA-compliant security stock with all six standard fraud deterrent features as part of every order. For a detailed description of each security feature in the paper, see our check stock paper guide and our check register guide for tracking issued checks.

How ABA Security Paper Stops Fraud

Every Checkomatic check ships on the same ABA-compliant security paper used by bank-issued checks, with six built-in fraud deterrent features that address the most common fraud methods directly.

Chemically Reactive Paper: Stops Check Washing

Chemicals are impregnated into the paper fiber during manufacturing. When any washing solvent is applied to the check surface, the reactive chemicals produce a permanent, visible color change or stain. This reaction cannot be reversed or concealed. A washed ABA-compliant check shows irreversible evidence of the chemical attack even after the fraudster rewrites the fields, making the alteration detectable at deposit.

Genuine Foundry Watermark: Stops Basic Counterfeiting

The watermark is embedded in the paper fiber during paper manufacturing, not printed on the surface afterward. It is visible only when the check is held to light and cannot be reproduced by any printer, copier, or scanner. A counterfeit check printed on plain paper will not have a genuine watermark, and a check with a surface-printed fake watermark will not show the correct transmission pattern when held to a light source.

Microprinting: Stops Photocopying and Scanning

Microprinting along the signature line appears as a thin rule to the naked eye but resolves as repeating text under 5x magnification or more. No photocopy or scan can reproduce microprinting accurately because consumer-grade copying equipment cannot achieve the resolution needed to replicate text at that scale. A check copy that lacks readable microprinting under a loupe is not a genuine check.

Heat-Sensitive Thermochromic Ink: Allows Instant Verification

The thermochromic element on the check (typically a padlock icon or specific printed area) disappears when the check surface is warmed by rubbing with a finger and reappears when released. This allows a bank teller or anyone holding a check to perform an instant authenticity test without equipment. A counterfeit check printed with standard toner or ink will not have a functioning thermochromic element.

Void Pantograph: Stops Copying and Check Cooking

The background design of ABA-compliant checks contains a hidden VOID pantograph pattern printed at a line density the human eye cannot resolve as text at normal reading distance. When the check is photocopied, scanned, or photographed for digital manipulation (as in check cooking), the pattern renders visibly as VOID across the copy. This makes any copy of a genuine check immediately identifiable as a copy, not the original.

UV Fluorescent Fibers: Stops Counterfeit and Cooked Checks

Invisible fibers distributed throughout ABA-compliant security paper glow distinctively under ultraviolet light. Plain paper, printer paper, and cardstock do not contain these fibers and do not glow under UV verification. Bank counter UV light check verification lamps can confirm the presence of UV fibers in seconds, immediately distinguishing a genuine check from a cooked or counterfeited substitute printed on non-security stock.

Positive Pay for Businesses

Positive pay is a bank-provided fraud prevention service for business checking accounts. When you issue checks, you upload a file to your bank containing the check number, amount, and payee for each issued check. When any check presents to your account for payment, the bank's system automatically compares the presenting check against your issued-check file. Checks that match are paid automatically. Checks that do not match (wrong amount, wrong check number, unknown check number, wrong payee) are flagged as exceptions and held for your review.

You review exceptions in your bank's positive pay portal and either approve or reject each one. Rejected checks are returned unpaid. This process catches counterfeit checks, altered check amounts, and unauthorized checks drawn on your account before they clear, rather than after the loss has occurred.

Most banks offer positive pay to business checking customers, often with no additional fee or with a small monthly service charge that is trivial compared to the potential loss from a single fraudulent check clearing against a business account. If your business issues checks for payroll, vendor payments, or any regular purpose, ask your bank about positive pay before your next check order.

For businesses managing high check volumes, the manual business checks, computer business checks, and QuickBooks-compatible checks at Checkomatic all ship on ABA-compliant security paper, giving the physical fraud deterrence layer of security paper protection alongside the systems-based protection of positive pay.

What to Do If You Receive or Deposit a Fraudulent Check

If you suspect a check is fraudulent before depositing it, do not deposit it. Contact the issuing bank using an independently sourced phone number to verify the check. Report the suspected fraud to your local law enforcement and to the Federal Trade Commission at reportfraud.ftc.gov. If the check arrived by mail, report it to the US Postal Inspection Service at postalinspectors.uspis.gov or by calling 1-877-876-2455.

If you have already deposited a check and later discover or suspect it is fraudulent, act immediately. Contact your bank's fraud department before any funds from the provisional balance are withdrawn or transferred. Explain that you believe you deposited a fraudulent check and ask the bank to reverse the provisional credit and investigate. If you have already wired back funds from a fraudulent overpayment, contact your bank immediately and ask whether the wire can be recalled. Wire recalls are time-sensitive and not always successful, but a same-day attempt has the best chance.

Intentionally depositing a fraudulent check, even if you later claim you did not know it was fake, can result in account closure and potentially criminal liability depending on the circumstances. If you received the check as part of an unsolicited offer, online transaction, or sweepstakes-style scenario, do not deposit it regardless of how convincing it appears.

Why Checkomatic Checks Carry Full ABA Security

Checkomatic has manufactured personal and business checks in Monroe, NY since 1997. Every check we produce ships on ABA-compliant security stock with all six standard fraud deterrent features built into the paper. Security is not a tier, an upgrade, or an option. It is the baseline for every order, whether a personal checkbook in blue or a full case of QuickBooks computer business checks.

The CPSA padlock icon on our ordering pages confirms Checkomatic's membership in the Check Payment Systems Association and compliance with ABA security paper standards. This is the same certification that qualifies checks from any manufacturer to be accepted at all US financial institutions.

Ordering checks that resist fraud starts with the paper. Our personal checks, business checks, blank check stock, and all formats in between ship with the chemically reactive paper that stops washing, the void pantograph that stops copying and cooking, the UV fluorescent fibers that allow instant verification, the microprinting that stops photocopy replication, the heat-sensitive ink that allows manual verification, and the genuine watermark that confirms the paper's authenticity.

For a deeper explanation of each security feature and how they interact, see our check stock paper guide. For a complete check fraud protection overview and broader context of check fraud types and how businesses protect themselves, see our check fraud scams guide and our check fraud prevention guide.

The Short Version on Check Validity and Fraud Prevention

Check fraud has increased substantially, driven primarily by mail theft and the accessibility of digital photo editing tools that make check cooking easier than ever. Suspicious Activity Reports related to check fraud nearly doubled between 2021 and 2023 according to the FBI.

A valid check requires a payee name, matching numeric and written amounts, a date, an authorized signature, and a correct MICR line drawn on a real account at a real financial institution. Post-dated checks, stale-dated checks, checks with stop payment orders, altered checks, and checks on closed or nonexistent accounts are all legally invalid in different ways.

Verifying a received check involves physical inspection of paper quality, MICR line appearance, edge texture, check number consistency, and security features, followed by bank verification using an independently sourced phone number. The overpayment scam relies on the timing gap between funds availability and check clearing. Never send money back from a check to someone you do not know personally.

Protecting outgoing checks means using black gel ink, filling all fields completely, mailing directly at post office counters, and ordering checks on ABA-compliant security paper that resists washing, copying, counterfeiting, and digital manipulation. Business operations should implement positive pay through their bank. Both measures together provide the most complete defense against check fraud for organizations that regularly issue paper checks.

Frequently Asked Questions

How can I tell if a check is valid?

A valid check has a real bank name, logo, and address; a complete MICR line with dull, flat magnetic ink (not raised or shiny); matching check numbers in both the upper right corner and the MICR line; at least one perforated or rough edge; matte paper that does not feel glossy or slippery; and ink that does not smear when slightly dampened. For any check of significant value, call the issuing bank using its official website phone number to verify the account and check are legitimate. Do not use the phone number printed on the check itself to verify it.

What is check washing and how does it work?

Check washing is check fraud where criminals apply household chemicals including acetone, bleach, or nail polish remover to a stolen check to dissolve the ink in the payee name and dollar amount fields, while leaving the authorized signature and account information intact. After the original information is removed, the fraudster rewrites a new payee name and a larger dollar amount. Checks printed on ABA-compliant chemically reactive security paper resist this method by producing a permanent, visible stain reaction when washing solvents are applied. Writing checks in black gel ink also significantly increases resistance to washing, since gel ink penetrates deeper into paper fibers than ballpoint or felt-tip ink.

What legally makes a check invalid?

A check is legally invalid when it lacks a required element (missing payee, missing signature, missing MICR line), when it is drawn on a nonexistent account or a closed account, when a stop payment order has been placed on it, when it is altered after signing, when it is more than six months old (stale-dated), or when it is deposited before its written future date (post-dated) contrary to the account holder's intent. A check written on an account with insufficient funds is not technically invalid but will be returned unpaid NSF when processed.

What is check cooking and how is it different from check washing?

Check cooking is digital check fraud where a criminal photographs or scans a stolen check, edits the payee and amount using photo editing software, and prints multiple copies on a consumer-grade printer. Unlike check washing, which alters the physical check, check cooking creates new counterfeit documents from a digital image of the original. The copies contain the real routing number, account number, and authorized signature from the original, but are printed on plain paper rather than ABA-compliant security stock. The void pantograph in genuine ABA-compliant checks (which shows VOID when scanned or copied) and the UV fluorescent fibers (which glow under UV light in genuine security paper but not in printer paper) are the primary detection tools for cooked checks.

Does ordering checks from a third-party manufacturer reduce security?

No. Checks from a CPSA-certified third-party manufacturer like Checkomatic use the same ABA-compliant security paper as bank-ordered checks. The six security features (chemically reactive paper, watermark, microprinting, heat-sensitive ink, void pantograph, and UV fluorescent fibers) are manufactured into the paper before printing and are identical across any order on the same security stock. The CPSA padlock icon on a manufacturer's ordering page confirms they meet Check Payment Systems Association standards. Checkomatic ships every personal and business check on ABA-compliant security stock with all six features included as standard on every order.