Adair's Traffic Light Chips (FT)

Three chips - one red, one yellow (amber) and one green - are covered with a pocket handkerchief. The red chip is removed and the magician states, "Red is for stop." He then brings out the yellow chip saying, "Yellow means get ready." That leaves "Green for Go." When the spectator undrapes the handkerchief, there is only one chip... but its color is gone - it's absolutely clear and transparent.