One Thing About Acetone I Need A Clearer Answer On

Because I don't use it under those conditions. Even to someone like me who is unafraid to "conserve" a coin, there are some you simply don't touch.

There is a lot more to the story about Acetone usage than most realize. Many soak or dip a coin in Acetone and later claim it effected the coins. However, those are usually the ones that use the same Acetone over and over and over. Sort of like taking a bath in water that lots of other people just did. Or washing a car with water from a well.
Also, many take a coin out of Acetone and allow it to just dry. Nothing wrong with that except occationally some of the Acetone that just evaporated had whatever was on the coin in it and as it evaporates, the residue left on the coin is the same as before only not as much.
And as you already noted if there was something on a coin that prevented some places to tone and the Acetone removes that, yes you know have a odd looking coin. Some toned, some not.


AND not EVERYONE is OK using it. Many people would rather not mess with a coin. Many do not use Acetone for many reasons and what you mentioned is only one.
It is expensive. It is dangerous. Should not be used indoors if possible. Should be really carefull with it around kids. You have to be carefull around a car since it is not really to good for the paint job.