To clean or not to clean your metal deting finds
The decision whether to clean a coin really depends on its age, rarity and its metal-alloy composition. The bottom line is DON’T clean coins except to gently wash them with water unless you can see any benefit of doing so.
The following phrase applies not just too chemical cleaning but to all cleaning. “We must do it the right way and appropriately!” Polishing with abrasives such as Brass cleaner, or any other metal polishing pastes or compounds is the wrong way and possibly one of the most damaging things you can do.
Using caustic chemicals such as ammonia or some other form of alkali whilst still not ideal is better than using abrasives and does not involve the kind of heavy-handedness polish does.
Electrolysis is only used for cleaning modern coins found on a beach, it will quickly destroy ancient coins.
TIP : Some Roman Bronze coins can be cleaned by soaking them in olive oil for a number of weeks, this will soften the contamination and allow safer cleaning with a soft toothbrush.
TIP : Silver hammered coins can sometimes be cleaned by placing them in a square of baking foil, then adding a small amount os saliva before wrapping them in the foil tightly.
You will feel the foil getting hot due to a chemical reaction, after a minute or so unwrap the foil and inspect the coin.