Display the coin in your hand, and then rub it into your elbow, announcing you are going to make it disappear! After a few moments drop the coin onto the table and say it usually works better with the other hand.
Pick the coin up and pretend to put it into the other hand. Then, pretend to rub "the coin" into your elbow, while the hand that is really holding the coin goes up behind your ear. Drop the coin into the back of your shirt collar, and then show that the coin has vanished, and both hands are absolutely empty!