a WAY BETTER way to do this is get three band new pennies.  On the bench grinder, shave the face off one, the back off one, and both sides of of the other one.  Thes in some muriatic acid. The acid will polish the copper shell and eat the inside metal.  Watch it closely off and on for about 30 minutes.  After this you have a perfect face, back and side ring.  You can grind of a fourth penny's faces and side then glue it to this one.  However, I like to to take a little piece (tiny of lead) and put it inside.  Then just glue it shut with a big air pocket.  This makes for an even cooler trick.  THE FLOATING PENNY that looks feels and weighs the same as a regular penny.

I knew that milling machine downstairs would be useful for something...

I made one of these once, you can do a pretty good job of removing hte tails side with a dremel, and it works really well for making the edges of the coin smooth, too.

regular sandpaper wont work though it just rips so u would need a bench grinder

also instead of  dustoff id take a more dangerous approach (danger is awesome) and open up one of those airhorn cans and use the liquid in there (which can actually give u frostbite) to pour on the coin with the super glue.

cool i gotta try it out but i dont get why you would super glue it for a second time does it change color or what

 This is how to do frozen by adam grace!!!

whats the point in freezing it again? colder temperatures make the superglue evaporate slower i thought.

do you have to use the dust off freeze thingy????????

Perhaps another way, rather than a jeweler's saw, would be to sand the coin down to approximately half their thickness and then glue them together. By the way, defacing ANY currency is only illegal if you have the intent to pass it off as legitimate afterward.

Another way to accomplish this feat is to use a jewelry saw to "split" both coins in to halves. Then sand all of the halves using your favorite sanding tool. You will glue the like halves using JB Weld. When dry, sand the edges with finer, and finer sand paper to achieve a mirror polish. This will produce 2 double sided "MAGIC" coins that are much harder to detect as gaffed coins. You could even add a steel shim to make the coins magnetic. Magnetic and double sided....that would be MAGIC. Take care!

wow i was expecting something better than just gluing 2 coins together

Harvey Dent was the district attorney.

Defacing US currency is frowned upon. Perhaps a token or other non-protected coin shaped object would be in order?