This was the forerunner to Steve’s Quick Change shown here using a bulldog clip as a switch device as credited to Bob Ostin.
Effect: Performer takes a borrowed fifty cent piece and inserts it into a spring clip where it is clearly visible. He shows hands to be otherwise empty. He holds clip with coin over spectator’s hand and releases coin. Coin changes into a brass washer AS IT FALLS INTO SPECTATOR’S HAND. Washer can be examined by x-ray. Spectator’s reaction is indescribable.
(Notice: Includes: Printed Instructions.)( Post Source: martinsmagic.com - click for details )