CLARKSVILLE, Tenn. -- The city of Clarksville has had several problems with customers trying to use fake money over the last few months.

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Now, police said criminals have new targets and new tactics that include using the bogus cash during pizza deliveries.

The owner of Michaels Pizza, Daniel Scott, is pretty pro-active when it comes to fighting funny money.

"I mark the larger denominations when they come in across the counter but don’t really look on the smaller denominations," said Scott.

For business owners, that's fairly typical.

"Normally, they're $50s and $100s. They're larger denominations," said Ted Denny, public information officer for the Montgomery County Sheriff's Office.

But it seems the criminals have picked up on that, and they're using it to their advantage.

Police said counterfeiters struck twice Thursday night at two different pizza joints, striking unsuspecting and busy pizza delivery boys.

"It was during the dinner rush, so we didn't catch it until we were making the night deposit," said Scott.

Fake $5 bills were being used, police said. They turned the two fake $5s into evidence.

"It was fairly obvious, once we started looking closely at it, that it was a fake," said Scott.

Deputies said criminals are constantly coming up with new ways to break the law. To stay ahead of them, business owners are going to have to start checking their $1s and $5s, too.

"Criminals are not always stupid. It’s a shame some of them are brilliant. They're very smart individuals, but they want a quick dollar," said Denny.

Authorities have not named any suspects or leads for either case.