Currency Exchange

A dollar bill is shown between two plastic sheets. The plastic pieces have been fastened with rubber bands and a padlock has been locked through a corner of the sheets and the bill. A spectator is asked to initial the bill through a hole in the piece of plastic. The magician borrows another dollar bill and signs it. The spectator is given the padlocked bill to hold. A handkerchief is placed over the bill. The magician places the borrowed bill under the handkerchief and instantly brings it back out again. When the spectator checks the signature, he's amazed to see that this is the bill that was locked up that he had signed! When the bill in the plastic is unlocked by the spectator, it is discovered to be the borrowed bill signed by the magician!