(WTNH) — Check washing — a decades-old bank fraud scam — is running rampant again, government officials say. We’re Stretching Your Dollar with what to look out for to protect your money.

Experts say that if you send and receive checks via mail, you may be vulnerable.

“Check washing is a type of fraud where the scammers get a hold of legitimate checks that you may write for a utility bill or as a gift to a loved one,” John Mreyault of the National Consumers League said. “And they take that check and they put it into a chemical solution. Usually, it’s something like acetone that you can find in most nail polish removers, and that allows them to get the ink that you have used to write the check off of the check.”

At that point — crooks have a blank slate.

“Once the check dries, you can write whatever you want/ We’ve heard of scammers using taking, you know, just the name off and not taking off a whole number,” Breyault said. “Let’s say it’s a $50 check. They’ll make it $150 check.”

According to the United States Postal Inspection Service, they receive more than $1 billion in counterfeit checks and money orders every year. This year, the agency has blasted warnings to consumers to help them avoid being the next victim.

“Those public blue mailboxes that you see in your corner are being checked less often,” Breyault said. “The Postal Service is reducing the number of those blue boxes. And so more mail is going to be put into the ones that are still there, which makes them attractive targets to scammers who can do things like wait until after the last pickup.”

Even if you don’t use the public mailboxes, your personal inbox is still prey.

So, the best solutions to keep your money safe? Go paperless or use an “indelible gel black ink” pen that is more difficult to take off the paper.