Check Washing and Mail Theft — The Envelope That Empties Your Account

What Is Check Washing?

Check washing is a fraud technique where a thief steals a physical check and uses chemicals — most commonly acetone, bleach, or brake fluid — to erase the ink for the amount and payee name while leaving the signature and account numbers intact.

The blank check is then rewritten for a larger amount, to a different payee, and cashed or deposited.

Because your signature and account information are genuine, banks frequently honor washed checks without detecting the fraud. Victims often don't discover the problem until they review a bank statement.

How Checks Are Stolen

USPS mailbox theft is the most common vector. Blue collection boxes are targeted because they may contain dozens of outgoing checks, and many mailboxes can be opened with a master key. Arrests of postal workers who sold these master keys have increased significantly.

Home mailbox theft — your incoming and outgoing mail both contain valuable information.

Mail forwarding fraud — attackers submit change-of-address forms to divert your mail to a different address.

Porch and lobby theft — less common for checks but relevant in multi-unit buildings where mail is left in unsecured lobbies.

Why Check Fraud Is Growing

Despite the shift to digital payments, billions of checks are still written in the US each year — primarily for rent, services, and business payments. As other fraud vectors become harder (card chips, better online fraud detection), criminals are returning to paper.

The FBI estimates check fraud losses exceed $20 billion annually in the US.

Protecting Yourself

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Use Electronic Payments Instead

The simplest protection is to not write checks. Use ACH transfers, bill pay through your bank, or wire transfers for anything significant. Venmo and Zelle work for person-to-person payments.

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Use a Gel Ink Pen

If you must write a check, use a gel ink pen (not ballpoint). Gel ink penetrates the paper fibers and is much harder to remove with chemicals without visibly damaging the check.

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Mail Checks at the Post Office

Don't leave outgoing checks in your home mailbox with the flag up, and don't drop them in blue collection boxes. Take them inside a post office or hand them to a postal worker.

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Use "Positive Pay" If Available

Many business bank accounts and some personal accounts offer positive pay — you submit a list of checks you've written, and any check that doesn't match is held for your approval before being honored.

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Review Your Bank Statements

Fraudulent checks can take weeks to appear. Review statements regularly and report anything you don't recognize within your bank's dispute window (typically 30–60 days for checks).

If a Check Has Been Washed

Bottom Line

Check washing is a low-tech attack that causes high financial damage. Use electronic payments whenever possible, use gel ink if you must write checks, and never leave outgoing mail with checks in an unsecured mailbox.

Protect Yourself Today

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