Silver Extraction by Vernet - Trick

EFFECT: The magician shows a half dollar to the audience and asks a spectator to hold it in her hand. He takes a lighter and moves the flame around her hand "to heat up the coin", explaining that he will extract the metal from the coin. The magician then reaches over to her hand and extracts a small lump of silver! When the spectator opens her hand she is holding a completely clear half dollar!