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Check Washing Scams: The Check You Mailed Can Be Rewritten for Thousands

By Muhammad Imran · Reviewed for accuracy against FinCEN and U.S. Postal Inspection Service guidance · Last updated October 2026.

Quick answer: Yes. This one's real, and it's booming. A check you drop in the mail can be stolen, soaked in chemicals that dissolve your handwriting, and rewritten to a stranger for a much bigger amount. The money comes straight out of your account, and you may not notice for weeks. The good news: a black gel-ink pen, mailing from inside the post office, and one free USPS service. Informed Delivery. Shut down most of it.

You've written checks the same careful way for decades. Payee, amount in numbers and in words, signature at the bottom. What nobody told you is that the envelope you drop in the mailbox has become one of the most hunted objects in American crime.

In February 2023, FinCEN. The Treasury Department's financial-crimes bureau. Issued a nationwide alert: check-fraud reports filed by banks had nearly doubled in a single year, from more than 350,000 in 2021 to more than 680,000 in 2022. And it didn't slow down. In just the six months after that alert, banks reported another $688 million in suspicious mail-theft check fraud.

This guide shows you exactly how check washing works, the 5 signs a check of yours was washed, the simple system that protects every check you mail. And what to do, step by step, if it already happened. And hear this first: if it happened to you, you did nothing careless. Thieves are prying open locked collection boxes and robbing mail carriers for their master keys. This is organized crime, not a mistake on your part.

🔑 The one fact that settles it: the wash removes only the ink you added. Your signature, your account number, and your bank's numbers stay printed right on the check. A stolen check is a signed, blank withdrawal slip from your account. Which is why everything below focuses on two things: ink that can't come off, and a mailbox the check never sits in.

How check washing works, step by step

Step 1. The theft. FinCEN says criminals target two places: the big blue USPS collection boxes and unsecured home mailboxes. They fish envelopes out with sticky makeshift tools, pry boxes open, or use stolen and counterfeit master keys. The same keys carriers use, which is why carrier robberies have spiked. What they're hunting is paper with value: your bill-payment checks going out, and checks coming in. FinCEN notes they routinely steal personal checks, business checks, tax refund checks, and government-assistance checks such as Social Security payments.

Step 2. The wash. Back at a kitchen table, the thief soaks or swabs your check with common chemicals. Acetone, the stuff in nail-polish remover, is the classic. Ordinary ballpoint ink dissolves and lifts away. The printed parts of the check don't. A minute later, your check looks half-blank: no payee, no amount. But your signature and account numbers are untouched.

Step 3. The rewrite. Now the thief writes in a new payee. Themselves, or a "money mule" they've recruited. And a new amount, often hundreds or thousands of dollars more than you wrote. A $68 electric bill becomes a $6,800 payday.

Step 4. The cash-out. The rewritten check gets deposited at an ATM or by phone app, deliberately avoiding a teller who might ask questions. The money is withdrawn or wired onward fast. Usually long before your statement arrives.

What thieves do with a stolen check

When FinCEN analyzed more than 15,000 reports of mail-theft check fraud from 841 banks, it found three endings for a stolen check:

  • 44% were altered and deposited. Washed and rewritten, the classic check-washing play.
  • 26% were used as templates. The thief copies your account and routing numbers to print counterfeit checks, so one stolen check becomes many.
  • 20% were fraudulently signed and deposited. Cashed as-is, with a forged endorsement.

That second number matters for you: even if a stolen check is "only" for $40, your account numbers are now in criminal hands. It's why the recovery steps below include watching the account. And why closing it is sometimes the right call.

Why this scam works

Checks feel safe because they're familiar. Most of us have mailed them for 50 years without a problem, so the envelope doesn't register as a risk. But notice what actually protects a check once you write it: nothing but paper and privacy. The moment it leaves your hand, you can't watch it, lock it, or confirm who touches it.

Thieves stack the rest of the deck. The raised red flag on your mailbox announces to everyone driving past that outgoing mail is waiting. A blue collection box sits unguarded overnight and all weekend. And discovery is slow by design: most victims only learn the truth when a monthly statement arrives, or when the electric company sends a "past due" notice for a bill they know they paid. Criminals count on that weeks-long gap. The fix isn't suspicion. It's a system, and it's below.

5 signs your check was washed

  • A check cleared for a different amount than you wrote. Usually much more.
  • The payee says they never received your check. But your bank shows it as paid.
  • The check image in your online banking shows handwriting that isn't yours, or a payee name you don't recognize.
  • You get "past due" or late-fee notices for bills you mailed payment for weeks ago.
  • Mail you were expecting never arrives. A refund or benefit check shown in your Informed Delivery email never reaches your box.

The safe-mailing system: how to protect every check

  1. Write with a black gel-ink pen. Gel ink soaks into the paper fibers and resists the chemical wash; ordinary ballpoint ink lifts right off. Postal inspectors and bank security experts recommend it. It's a two-dollar pen that defeats the entire trick.
  2. Fill in every blank. Leave no gaps on the payee or amount lines. Draw a line through any leftover space so nobody can add digits or words. Never sign a blank check, and never write your Social Security or driver's license number on one.
  3. Mail from inside the post office. Hand the envelope to a clerk or use the collection slot inside the building. If you must use an outdoor blue box, drop your mail before the last pickup of the day. Never let a check sit overnight, on a Sunday, or over a holiday. And never mail checks from your home mailbox with the flag up: that flag is a sign that says "money here."
  4. Sign up for Informed Delivery. It's a free USPS service (sign up at usps.com) that emails you photos of the letter mail headed to your address each day. If a check shows in the email but never arrives, you know the same day. Not next month. Signing up also stops a thief from registering your address first.
  5. Empty your mailbox promptly, and hold mail when you travel. Don't let mail sit overnight. Going away? USPS Hold Mail keeps it safely at the post office until you return, or ask a trusted neighbor to collect it daily.
  6. Pay online or by ACH where it's safe to do so. Your bank's own bill-pay service or an automatic ACH payment for the electric, gas, and phone bills removes the paper check from the mail entirely. Set these up only through the bank or company site you typed in yourself. Never through a link in an email or text.
  7. Review your cleared checks. At least weekly in online or mobile banking. Or on every statement. Check the amount and the payee on each check that cleared, and view the check image for anything important. For big checks, confirm with the payee that it arrived.

What the postal inspectors are doing about it

  • Project Safe Delivery. The joint USPS–Postal Inspection Service crackdown launched in May 2023. Has produced more than 2,400 arrests for mail theft and related crimes and a 27% reduction in letter-carrier robberies.
  • From 2019 through 2024, postal inspectors arrested almost 9,300 suspects for theft of mail and packages.
  • The Postal Inspection Service runs a standing awareness campaign with the American Bankers Association Foundation on exactly these check scams. The gel-pen and post-office advice above comes straight from that guidance.
  • Your report genuinely helps: FinCEN says bank and victim reports are how inspectors map criminal networks and identify victims for restitution. Reporting isn't paperwork for its own sake. It's how cases get connected.

Check washing vs. fake checks: what's the difference?

These two get confused constantly, and the difference matters because the danger. And the fix. Are opposites.

A fake check scam is about a check that comes TO you. A stranger sends you a check. An "overpayment" for something you sold, a mystery-shopper "job," a prize. And asks you to deposit it and send part of the money back. The check is counterfeit. Your bank makes the funds available before the check truly clears, you send real money out, the check bounces, and you owe the bank. The trap is depositing. We cover that playbook in full here: Fake Check & Overpayment Scams.

Check washing is about a check that comes FROM you. The check is 100% real. You wrote it. A thief steals it from the mail and rewrites it, and your real money leaves your real account to the wrong person. The trap is mailing.

One sentence to keep them straight: if a stranger's check arrives asking you to deposit it, that's the fake-check scam; if your own mailed check gets altered, that's check washing.

I think my check was washed. What now?

  1. Call your bank today. Use the number on your card or statement. If the check hasn't cleared, ask for a stop payment. If it has, report it as an altered check and ask about closing the account and opening a new one. Remember, thieves may have copied your account numbers to print counterfeits.
  2. Report the theft to the Postal Inspection Service at uspis.gov/report or 1-877-876-2455. Postal inspectors investigate mail theft, and your report helps them connect your case to the network behind it.
  3. File a police report with your local police department. It's an official record of the crime, and your bank may ask for the report number during its investigation.
  4. Tell the person or company you meant to pay. Explain what happened, ask them to waive any late fee, and arrange a replacement payment a safer way. Bank bill pay or an in-person payment, not another check into a mailbox that may be watched.
  5. Watch everything for a while. Turn on bank alerts, review every cleared check, and if other mail with personal information went missing too, consider a credit freeze. For the complete step-by-step playbook, see our guide: Clicked a Scam Link? Do This Now.

Act the same day. Banks can require prompt notice of an altered check, and the trail for postal inspectors is warmest right after the theft. If checks are being stolen on your street, your neighbors need the warning too. Mention it to them and to your mail carrier.

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What is check washing?

Check washing is when a thief steals a check you mailed, uses chemicals to erase the payee name and amount you wrote, and rewrites the check to themselves. Usually for much more money. Your signature and printed account numbers stay on the check, which is why the altered check can pass at a bank.

How can I tell if my check was washed?

Check your bank account for checks that cleared for a different amount than you wrote, or paid to someone you don't recognize. If the company you paid says it never received your check but your bank shows it as paid, that's the classic sign. Viewing the check image in online banking shows you exactly whose name is on it now.

What kind of pen should I use to write checks?

A black gel-ink pen. Gel ink soaks into the paper fibers, so thieves can't wash it off the way they can with ordinary ballpoint ink. Postal inspectors and bank security experts recommend it. A small change that defeats the chemical wash.

Is it safe to mail a check at all?

It's safest to hand the envelope to a clerk inside the post office or use the collection slot inside the building. If you use an outdoor blue box, drop your mail before the last pickup of the day. Never leave checks sitting overnight, on Sundays, or over holidays. And never mail a check from your home mailbox with the flag up.

My check was washed and cashed. Will I get my money back?

Often, yes. In many cases banks restore money taken by an altered or forged check, but timing matters. Report it to your bank the moment you spot it: banks can require prompt notice, and waiting weeks can complicate your claim. There's no guarantee, so speed is everything. Ask about closing the account, and keep copies of everything.

Where do I report check washing or mail theft?

Report mail theft to the U.S. Postal Inspection Service at uspis.gov/report or 1-877-876-2455. Postal inspectors investigate these crimes. Also call your bank immediately and file a report with your local police; your bank may ask for the police report number.

Sources: FinCEN alert FIN-2023-Alert003, February 27, 2023 (check-fraud reports: more than 350,000 in 2021, more than 680,000 in 2022; 299,020 mail-theft complaints received by USPS, March 2020 – February 2021); FinCEN Financial Trend Analysis, September 9, 2024 (15,417 reports from 841 financial institutions, more than $688 million in reported suspicious activity; 44% of stolen checks altered, 26% used as counterfeit templates, 20% fraudulently signed); U.S. Postal Inspection Service mail-theft prevention guidance (uspis.gov); Project Safe Delivery results, USPS/USPIS news releases (2025). Last updated October 2026.

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