Bankers have discovered a surge of counterfeit bills recently circulating between Dinkytown businesses.

Since opening at the beginning of February, the TCF Bank branch in Dinkytown has spotted more fake bills than some business owners say they usually see all year.

TCF Manager Marlene Woo said at a Dinkytown Business Alliance meeting last month that at the old Stadium Village location, counterfeit bills would make it to the branch only once or twice a month. In the two weeks leading up to the meeting, Woo had seen five counterfeit bills come to the bank.

Woo said at the meeting that all of the fake bills were $20 notes and varied greatly in quality. Some, she said, bled ink when dipped in water.

Local business owners said they have numerous measures that may work to keep their businesses from taking in unwanted counterfeits.

A well-trained staff and an overwhelmingly non-cash business may discourage potential counterfeiters, said Blarney Pub and Grill Owner and DBA President Mike Mulrooney.

“The first thing that most of my staff will think is, ‘Why are they using cash?’ So that highlights them,” he said.

Randal Gast, owner of Dinkytown’s Qdoba Mexican Grill, said two to three fake bills come through his business in the course of an average year, but many of the scammers are less skilled than one might find in other parts of the state.

Gast said scammers are more likely to go after newer businesses with less experience dealing with fake currency.

One change that he has noticed is that people tend to use smaller bills for counterfeits than in past years to avoid scrutiny.

Ultimately, the bills were turned over to the U.S. Secret Service, which handles all currency issues.

Lou Stephens, special agent in charge for the Minneapolis branch of the Secret Service, said a large portion of counterfeit bills are passed out around the holiday season.

Stephens said roughly 22 percent of false bill exchanges are made between December and January, and the rest happen in the remaining months.

The creation of bills now is easier than it has ever been, he said, due to the availability of high-quality printers and computer equipment.

While there are many different ways that real currency can be authenticated, including watermarks and a special security thread along the left side of the bill, Stephens said one of the most difficult things to duplicate on a bill is the quality of paper.

Gast said at the meeting that he has identified a group of men who his businesses have refused to serve because he knows they use false bills.

When the Secret Service was founded — the same year President Abraham Lincoln was assassinated — about half of all currency in the U.S. was counterfeit, Stephens said.

False currency undermines confidence in real currency and in the economy as a whole, he said.

“It really is a form of theft,” he said.