There's an urgent warning from a Mount Vernon woman when it comes to mailing checks.

“How dare you go into someone’s account and steal like that," says Mount Vernon resident Rosalind Hunter Blain.

Blain says she recently put a letter containing a check inside the mailbox in front of the Fleetwood Avenue post office in Mount Vernon.

It was made out to her insurance, worth around $212.

But a couple of days later, she went to buy something and got a big surprise.

“When I got to the register, the young man said that my purchase was denied. I couldn’t believe that because I knew there was money in my account. I went over to my bank and I did an inquiry, it said I was overdrawn by $10,563," Blain tells News 12

Blain says the check was washed. The new amount put on it was $11,700.

She says her bank stopped the money from fully going through.

However, she is far from the first to be dealing with something like this.

“This is not a new scam. This is when somebody gets hold of your check, might be through the U.S. postal mail boxes, might be somebody gets a key to your mail box, could be mail just left around," says Claire Rosenzweig, who is the president and CEO of the Better Business Bureau serving Metropolitan New York.

Rosenzweig says thieves use chemicals to wash away what’s on the check.

She says some ways to protect yourself include bringing the letters directly into the post office or use electronic options for payments, if possible.

Blain still has a lot to sort out.

“They had to cancel my debit card, my checking account," Blain explains.

But she is thankful she is getting help from her bank and wants to make sure others have this on their radars.

"I call myself pretty corporate savvy and know my way around but what about the elderly that don't?" says Blain.

News 12 reached out to the Postal Inspection Service to see if it had had any other reports and are still waiting to hear back.

For more tips from the BBB on how to avoid these schemes, click here: https://www.bbb.org/article/scams/28998-bbb-scam-alert-protect-yourself-from-check-washing