Heres the secret which youll have to prepare ahead of time. Youll notice that the rings, card and coin are sitting on a piece of paper. You obtain a second sheet of the same paper and cut a circle that is the same diameter as the second (gimmicked) ring. This is glued onto the bottom of the second ring.
This figure shows how the circular piece of paper is glued to the bottom of the ring. When you lay the ring on top of a coin, the matching paper thats glued to the ring covers the coin and makes it look as if the coin has vanished. Its actually sitting underneath the paper thats attached to the ring.