How do you identify a counterfeit five dollar bill?

Answer 1

Besides the consumer methods (watermark, reflective ink, testing the paper), the Treasury can also check the plate numbers against the serial numbers for sequential bills, or do a mass spectrometer test of the ink or paper of the bill. The inks used are specifically designed, are changed slightly with each series, and are nearly impossible for the average counterfeiter to duplicate.

Answer 2

There are chemical pens that test for genuine currency paper in US bills. New bills will also have a "watermark" visible when you hold it up to the light, and a security thread running through the left center of the bill. The lightly tinted yellow-green "paper" (which is actually cotton and linen) has visible red and blue fibers in it.

Answer 3

u get near a light and put it below the light a little and look threw it if u can see the other side it real if not its fake