Effect : A spectator is given 3-6 crayons of different colors to choose. He selects one and hands it to you behind your back. You claim that you can tell what color the crayon is, simply by holding it. You then announce the color of the crayon, proving that you can do what you claimed!
Secret : When the crayon is behind your back you dig your thumbnail into the crayon and get some of the color under your nail. When you bring your hand around to your front you secretly sneak a peek at the daub of color under your nail and you know what color the crayon is.
Performance Tip: Don’t be too obvious about looking at your fingernail - you can tell the color quickly - so don’t take too long.
