Category:Cleaning of coins

English: Generally speaking, coins in normal circulation or in collections should never be cleaned or polished. Obviously, though, coins that have been found underground or underwater will need a certain amount of cleaning before they can be identifiable. Currently, less destructive methods of cleaning, namely ultrasonic cleaners, are available, and should be used in preference to older, more caustic techniques illustrated here. Wikipedia does not recommend the use of the tools and techniques described here, but lists them as examples of techniques and tools that have been used in the past by some coin dealers.