Use the tool to remove hard dirt on uncleaned coins. Instructions are included on how to use them.
When grinding - apply little to no pressure, so there is very little chance of scratching the patina. The tip is diamond dusted, and will slowly remove the dirt particles. If you hear 'squaks', you are likely on patina and should stop in that location.
I advise you to combine this tool with scrubbing with a toothbrush after water soaks.
