First possibility :
Give a spectator a 1 €uro coin and a 50 cents €uro to hold behind his back. Bet the spectator that you can remove one of the coins he is holding - without touching him!
When he opens his hand, the 50 Cents €uro has magically disappeared and a 1 €uro has taken its place! This version of Scotch and Soda is the finest made.
Second example :
You show the 2 coins and you put them in a glass and you cover it with a handkerchief. Shake it. Remove the handkerchief. A coin vanished. You can relocate it anywhere !
There are still lots of effect possible.