An acetone bath wouldn't hurt them, but I seriously doubt it would help them any either. Doesn't look like dirt, looks like tarnish and acetone won't have any effect on tarnish.
Hi Conder, I had sent Doug a message and requested him for his opinion. Doug agrees with you and others as per the following: Howdy Al No trouble at all, feel free to contact me about anything at any time. To answer your question, acetone won't do a thing or remove a thing from either of those coins. Acetone does not remove tarnish/toning at all. It will only remove some organic compounds, oils and PVC - that's it. If you want to remove the tarnish the coins will have to be dipped in a commercial coin dip - which is in reality nothing but an acid solution. Personally, I would not bother doing that. There are some collectors who actually like that kind of toning. So I would just sell the coins as they are and keep the ones you do like. If you have any other questions, ask away. Doug