Scam Spotlight Series: Check Washing Scams — How to Protect Your Money
October 23, 2026
Have you ever mailed a check to pay a bill, only to discover that someone changed the amount or the name of the person receiving the money? You could be the victim of a check washing scam.
Check washing is a type of check fraud that can affect anyone who writes checks, including individuals, families, and businesses. Criminals steal checks, often from the mail, and use chemicals or other methods to remove the original ink. They can then rewrite the check to themselves or another recipient, sometimes changing the dollar amount as well.
In this month's Scam Spotlight Series, we're shining a light on how check washing works, the financial impact it can have, and the steps you can take to protect your personal and business accounts.
What Is Check Washing?
Check washing occurs when criminals alter a legitimate check by removing or changing information written on it. Fraudsters may use chemicals to erase the payee's name and dollar amount while leaving the rest of the check intact. They can then write in a new payee, increase the amount, or do both.
For example, a check you wrote for $75 to pay a utility bill could be altered to appear payable to a criminal for $750.
Check washing often begins with mail theft. Criminals may take outgoing checks from unsecured mailboxes or public collection boxes, or steal delivered mail containing checks. Once they have a check, they attempt to alter it and deposit or cash it.
According to the Office of the Comptroller of the Currency (OCC), check washing is one form of check fraud involving the use of chemicals to erase ink and rewrite the payee or amount. The U.S. Postal Inspection Service (USPIS) warns consumers about this crime and recommends several ways to protect checks and mail.
The Impact of Check Washing and Check Fraud
Check washing can cause more than a temporary inconvenience. Victims may face unauthorized withdrawals, unexpected account balances, missed bill payments, time spent working with their financial institution, and uncertainty about whether additional checks have been stolen.
The problem also extends beyond check washing to other types of check fraud, including forged and counterfeit checks.
The USPIS reports that postal inspectors recover more than $1 billion in counterfeit checks and money orders every year. This figure reflects counterfeit checks and money orders recovered by postal inspectors; it is not an estimate of check-washing losses alone. Still, it highlights the scale of fraud involving checks and the mail.
For businesses, the risk can be especially concerning when criminals target payroll checks, vendor payments, or other large-dollar transactions. A single altered check may disrupt cash flow and create additional work for employees responsible for bookkeeping and account reconciliation.
The good news? There are practical steps individuals and businesses can take to make check washing more difficult and identify suspicious transactions sooner.
Real-Life Scenarios: How Check Washing Can Happen
The following stories are fictional examples created to illustrate common check-washing tactics. The characters and circumstances are not based on identifiable customers or specific reported incidents.
Example 1: How Emily Almost Lost Money Through a Personal Check
Emily, a homeowner, wrote a check for $185 to pay a home repair bill. She placed the envelope in her residential mailbox with the flag raised, expecting the postal carrier to collect it that afternoon.
A few days later, Emily checked her online banking account and noticed a check payment for $1,850. The transaction appeared to involve the same check number she had used for her repair bill, but the amount was ten times higher.
Concerned, Emily reviewed the check image available through her online banking account. She discovered that the original payee's name had been replaced with someone else's, and the dollar amount had been altered.
Emily contacted her bank immediately to report the suspected check washing. The bank explained the next steps for investigating the unauthorized transaction and advised her to review her recent account activity for any other suspicious items.
Emily also reported the suspected mail theft to the U.S. Postal Inspection Service.
The experience taught Emily an important lesson: even when you mail a check to a legitimate business, you cannot assume it will reach its destination safely. She began using online bill pay whenever possible and started taking outgoing checks directly to the post office instead of leaving them in her mailbox.
Example 2: How a Business Can Be Targeted by Check Washing
Riverbend Supply, a fictional small business, regularly mailed checks to vendors for inventory, equipment, and operating expenses. Its bookkeeping team kept a record of every payment and reconciled the business checking account each month.
One morning, the bookkeeper noticed a check for $8,400 that had cleared the account. The company's records showed that the check had originally been issued for $840 to a regular supplier.
After reviewing the cleared check image, the bookkeeper discovered that the payee's name and amount appeared to have been altered. The company had become a potential victim of check washing.
The business contacted its bank immediately, reported the suspected fraud, and began reviewing other outstanding and recently cleared checks. Management also reported the suspected mail theft to the U.S. Postal Inspection Service.
As the company reviewed its payment procedures, it recognized an opportunity to strengthen its controls. Riverbend Supply contacted its bank to learn more about Positive Pay, a check-fraud prevention service that can help businesses identify unauthorized or altered checks before they are paid.
With Positive Pay, a business generally provides its bank with information about the checks it has issued, such as check numbers and dollar amounts. The bank compares checks presented for payment against that information and flags exceptions for review. Depending on the service, payee verification may also be available.
Positive Pay is not a guarantee against every form of fraud, and its effectiveness depends on the service and how exceptions are handled. However, it can add an important layer of protection for businesses that continue to issue paper checks.
For businesses that write checks regularly, talking with your bank about Positive Pay and other fraud-prevention tools is a worthwhile step toward protecting company funds.
How to Protect Yourself From Check Washing
You do not have to stop writing checks entirely to reduce your risk. A few changes to how you write, mail, and monitor checks can help make it harder for criminals to succeed.
Use Black Gel Pens With Permanent, Fraud-Resistant Ink
One simple precaution is to write checks with a black gel pen designed to resist ink removal. The OCC specifically recommends black gel ink because it can be more resistant to check-washing chemicals than some other inks.
Consider pens that advertise permanent or proprietary ink technology, such as Uni-ball pens featuring Super Ink. These may offer an added layer of protection when writing checks. Look for the manufacturer's stated features, and remember that no pen makes a check completely immune to alteration.
Avoid using erasable pens or ink that can be removed easily.
Fill In the Payee and Amount Lines Completely
When writing a check:
- Write the recipient's full name clearly.
- Start the dollar amount close to the left side of the amount line to reduce the space available for alteration.
- Draw a line through any unused space on the written amount line.
- Write the numerical amount clearly and avoid leaving unnecessary blank space.
- Do not leave the payee field blank or sign a blank check.
These steps can make it more difficult for someone to change the information on your check.
Mail Checks Safely
Because check washing often begins with mail theft, how you send a check matters.
- Whenever possible, take outgoing mail containing checks to the post office and use an interior collection slot.
- If using a USPS collection box, check its posted collection time and deposit mail before the last pickup.
- Avoid leaving outgoing checks in your home mailbox overnight.
- Retrieve incoming mail promptly and avoid leaving it unattended for extended periods.
- If you are traveling, arrange to have your mail held or collected by someone you trust.
- Consider using a security envelope to conceal the contents.
The USPIS offers additional advice in its official check-washing guidance.
Consider Electronic Payments
If you have the option, use your bank's online bill pay service, an electronic payment, or another trusted digital payment method instead of mailing a paper check.
Electronic payments can reduce the risk associated with stolen paper checks, although they have their own security considerations. Always use official websites or trusted payment systems, and protect your login credentials.
Monitor Your Bank Account Regularly
Review your account activity frequently rather than waiting until the end of the month to reconcile transactions.
Look for:
- Checks clearing for amounts different from those you wrote.
- Payments to unfamiliar individuals or businesses.
- Check numbers that appear out of sequence or that you do not recognize.
- Checks that have not reached their intended recipients.
- Other unexplained withdrawals or account activity.
If your bank provides images of cleared checks, review them when possible. Check both the front and back for unfamiliar payee or endorsement information.
For businesses, timely reconciliation and clear procedures for tracking issued checks can help employees identify suspicious items sooner.
Ask Your Bank About Positive Pay
Positive Pay can be a valuable check-fraud prevention tool for businesses. It helps compare checks presented for payment with information about checks the business issued.
Depending on the bank's service, exceptions may include an unexpected check number, an altered dollar amount, or a payee mismatch. The business can then review flagged items and make a pay-or-return decision within the applicable deadline.
If your business issues checks for payroll, vendors, rent, or other expenses, ask your bank whether Positive Pay or another check-monitoring service is available and which options fit your payment process.
Follow Up on Checks That Do Not Arrive
If you mail a check and the recipient says it never arrived, do not ignore the discrepancy. Contact your bank promptly to discuss whether the check should be stopped or whether another protective step is appropriate. Follow up with the intended recipient and monitor your account for the original check clearing unexpectedly.
What Should You Do If You Suspect Check Washing?
If you notice an altered check or a suspicious transaction, acting quickly can help limit further harm.
- Contact your bank immediately. Report the suspected check washing, ask about disputing the transaction, and follow the bank's guidance on stopping outstanding checks or changing account details if necessary.
- Review recent transactions. Check for other altered checks, unauthorized withdrawals, or unfamiliar activity.
- Keep records. Save check images, account statements, transaction details, and any correspondence related to the incident.
- Report suspected mail theft. Contact the U.S. Postal Inspection Service online or call 1-877-876-2455.
- Contact local law enforcement when appropriate. Keep a copy of any report and provide it to your bank if requested.
Do not wait for additional suspicious activity before notifying your bank. Prompt reporting gives the bank an opportunity to investigate and explain what protective actions may be available.
Stay Informed and Protect Your Money
Check washing is a reminder that everyday financial habits can make a difference. Using black gel ink, mailing checks securely, monitoring account activity, and considering electronic payments can help reduce your exposure to check fraud.
For businesses, tools such as Positive Pay can provide an additional layer of oversight when paper checks remain part of normal operations.
At Rivers Edge Bank, we encourage our customers to stay informed, ask questions, and speak with their banking team whenever something does not look right. A quick conversation can help you identify potential fraud and determine the next steps.
Learn more about check fraud and prevention from these trusted resources:
About the Scam Spotlight Series:
Each month, we shine a light on the latest scams that fraudsters use to trick people into giving up their money or personal information. In 2024, consumers reported losing over $12 billion to fraud, with 20-29 and 70-79 year olds being the most targeted age groups, according to the Federal Trade Commission. By sharing real-life examples, we aim to uncover the tactics scammers use, helping you recognize and avoid their schemes. Along the way, we’ll also provide practical tips to safeguard yourself and your loved ones. At Rivers Edge Bank, your safety and security are our top priorities—because protecting your hard-earned money starts with staying informed. To learn more about cybersecurity best practices, visit our Cyber Security page.