Things are not always what they appear to be.

The holiday shopping season is getting underway and the Montrose Police Department says there has been an increase in the use of counterfeit bills recently.

Local businesses and cashiers are being reminded to be vigilant when it comes to transactions with large bills.

Detection pens used by most businesses to help detect fake bills are great tools, but they are not 100% accurate. Cashiers need to check for watermarks, security threads,  and small red and blue fibers in the paper.

The Monrose Police Department says these photos (above) are "extreme cases", but make the point that inconsistencies are easy to overlook when you are in a hurry.

It is also a good idea to check out the federal reserve website to educate yourself on what real money is supposed to look like. The best way to identify counterfeit bills is to become very familiar with that the real thing.