I build machines that smash an image on pennies... the way the law reads it is illegal to deface a coin FOR FRAUDULENT PURPOSES. basically you can mash, smash, drill for jewelrey, put it under a steam roller, or do any thing you want to a coin. What you cannot do is make a quarter look like a Susan B Anthony dollar to try to make it worth more. ps if you are using it to get money fraudulently it could be prosecuted, but in the case of stage "illusion" I doubt it would be considered fraudulent.
WWW.SquarePegRoundHole.multiply.com