THE SETUP

All you need to do this trick are five things:
Two pairs of pliers
Two quarters
An old rag or T-shirt

Now you place one of the quarters under the towel and grab it through the rag with one plier one one side and the other plier on the other side.    
The purpose of the rag is to hide the fact that you bent it with pliers and to prevent you from scratching it. Now you will have one bent coin and one that looks like the other but the other one is not bent.

                     THE PERFORMANCE
You ask your spectator for a quarter and they hand you one. The duplicate from before serves one purpose: If the spectator does not have a quarter, you have one. Either way, they inspect the coin which is perfect misdirection for you to reach into your right pocket and get the bent quarter into finger palm position. Now you are going to a move I call the French switch. It is like the french drop but it has one more key element. The key is to have the unbent coin in your left hand and to do the french drop, but you are going to have the bent coin in your right hand finger palm position, so after you do the french drop, you will be left with the bent coin in the hand the spectator thinks the unbent coin is in. Just to clear this up, they don't know that you have the bent coin until after you do the "french switch" and ditch the unbent coin in your left pocket.
Now you will be able to show the coin and hand it out. YOU ARE COMPLETELY CLEAN!!!
But just remember, this is a mind blowing trick so you must practice in front of a mirror and get comfortable with it.
Have fun