How do you identify counterfeit Confederate money?

Answer 1

Modern replicas of Confederate money (in fact, of all money) by law must have the word COPY or REPLICA worked into the design.

However, millions and millions of copies of genuine Confederate money were made for sale in gift shops and as memorabilia for many decades before that law went into effect. A lot of them were made by photolithography using artificially aged paper and can be very difficult for the average person to identify. Fortunately, many of the replicas were taken from a small set of genuine bills so it's often possible to cross-reference the serial numbers and/or signatures against lists of known copies.