Katie and I put a dime on some train tracks before a train went by. We'd both seen coins flattened by trains before, but not in many years. The dime came out so beautiful that we decided to put it on a necklace! As long as you have access to a train, you can make one too. Just flatten the coin by running it over with a train, then drill a small hole (we used a 0.063" drill) near the edge. Fashion a small ring out of some metal wire or old jewelry and then run a chain through. The coin is wonderfully antique-looking, and the coin markings are just barely visible.