Magician borrows a quarter, puts it in a spectators hand, waves his hand over it and it disappears. He shows his hand empty after it.

Secret :

There is magnet on the end of a pull going up his sleeve. He switchs the borrowed coin with a magnetic coin. He waves his hand over the spectators hand, magnet picks up the coin, he lets go of the magnet, it flys up his sleeve with the coin, then turns his hand over and shows it empty.