What is Check Washing? Understanding and Preventing This Growing Scam

In recent years, a classic financial scam known as check washing has been making a concerning comeback—even in our local community. As fraudsters develop new ways to commit financial crimes, it’s important for businesses and individuals to remain vigilant and informed.At Marshfield Medical Center Credit Union, your financial security is our top priority. Here’s what you need to know about check washing, how it works, and the steps you can take to protect yourself.

What is Check Washing?

Check washing is a type of fraud in which criminals steal a legitimate check, usually from the mail, and alter the details—such as the payee name and dollar amount—before attempting to cash or deposit it.

The fraudster typically uses chemicals or solvents to remove the ink from the check, leaving the signature and check number intact while changing the rest of the information.

Once altered, the washed check is often made payable to the criminal or an accomplice for a much larger amount than originally intended.

How Check Washing Happens

Most check washing scams begin with mail theft. Criminals often target mailboxes—especially outdoor blue USPS collection boxes or unsecured residential mailboxes—looking for envelopes that appear to contain checks.

After intercepting the check, they use common household chemicals to erase the original writing. The washed check is then rewritten and cashed or deposited, sometimes even before the intended recipient knows anything is wrong.

The Risks of Check Washing

Financial loss due to the altered amount.
Compromised account information, since routing and account numbers are visible on all checks.
Business disruption, particularly if an account must be closed or investigated.
Delayed vendor payments or missed donations.

Even if your financial institution is able to recover the funds, the process can be time-consuming and stressful.

How to Protect Yourself

While check washing is a serious threat, there are steps you can take to reduce your risk:

Use electronic payments whenever possible.
Avoid mailing checks from personal mailboxes; drop them off inside a post office.
Use gel pens or permanent ink that is resistant to washing chemicals.
Monitor your accounts frequently for unauthorized transactions.
For businesses, consider implementing positive pay services for additional fraud control.
Report suspicious activity to MMCCU or local law enforcement immediately.

MMCCU is Here to Help

If you believe a check you’ve written has been altered or stolen, contact us immediately at 715-387-8686. We’ll work with you to protect your account, investigate the incident, and prevent further fraud.

At MMCCU, we are committed to providing safe, reliable financial services and up-to-date information to help you protect your finances.