Scratchcard
A scratchcard is a card designed for competitions, often made of thin cardstock or plastic, where one or more areas contain concealed information which can be revealed by scratching off an opaque covering. Applications include cards sold for gambling (especially, lottery games and quizzes), free-of-charge cards for quizzes, fraudulent free cards encouraging calls to premium rate phone services, and to conceal confidential information such as PINs for telephone calling cards (otherwise known as recharge cards) and other prepaid services.