I purchased a Masada bronze coin in Israel for my son. We received a certificate of authenticity so we believe it is an authentic ancient coin. We asked if my son could wear it anywhere (as it was set in a pendant bezel) and the dealer said it is safe to wear in the shower as it has withstood thousands of years. Now, a year later, the coin has gotten blacker and is very hard to see the etchings. What can I do to remove the black so I can see the coin markings again?
Hi Denmother...... That is a good question. This is a very active forum and the place you posted this is mostly frequented by folks that collect US coins. And to a US coin collector, cleaning coins is taboo. The folks in the ancient forum here are an active and extremely educated group that don't have the qualms about cleaning a coin that US coin collectors tend to have. Hoping maybe a moderator can maybe move this to the ancients section where you would be certain to get some useful feedback. If not, I think you would do best to post your question in the ancients forum in a day or so.
I moved it and deleted the second thread. Any copper based coin does extremely well in dry desert like conditions , such as the coins location. But water and any chemicals such as swimming, soaking and prolonged showers can oxidize the surfaces of the coin. As was mentioned in the US coin areas, cleaning is not preferred there., especially copper/bronze as it can turn a pink color . Maybe they can help you here with it. Jim
It doesn't look bad to me, but I suspect that the darkening you've observed is due to the patina and remaining dirt absorbing natural sebaceous bodily secretions. When I get bronze coins that are clearly "greasy' from excessive handling or undesired treatment I dip 'em in acetone which dissolves the fat/wax/oils almost immediately.
Buy a replica coin he can wear. That way you wont have to worry. If you clean it you will destroy any value it has as a coin. Right now it looks just like it should.