For this 1 Minute Finger Tip you'll need a piece of card, a green wax crayon, some green poster paint, a paintbrush and a black felt tip pen. And a spare minute, of course! So limber up those Finger Tips and when you're ready, start the clock. Begin by writing a secret message on the card with the black felt tip pen. Next, cover the message completely with green wax crayon. Press quite hard! Then load up the paintbrush with poster paint and completely paint out the crayoned area and the message. And stop the clock! You've made a scratchcard. Once the paint has dried you can use a coin to scratch the paint away to reveal the message! And you can also use the idea for revealing messages in greetings cards!