Effect:

A coin disappears from your hand in spite of the fact that several people checked it is there.

Procedure:

Show all the spectators the coin on your palm and cover it with a handkerchief. Go up to the spectators individually and have them feel the coin under the handkerchief. The last person you approach is your secret assistant, who pretends to feel the coin but actually takes it off your palm. You can now pull the handkerchief away and show them that the coin has vanished!