Looks like glue to me. If you stick two coins together with a drop of clear glue and then pull them apart it leave an image of the other coin in the glue on the opposite coin. The glue if thin looks a lot like metal on the coin. I found a coin once that had glue on it and I thought it was an extra image in the coin. Someone on a coin forum told me to try acetone and it came right off. Could have sworn it was extra metal. Try a little acetone on it and see if it comes off.


















