I flipped it about every 30minutes or so. Carl was right. What happened to the obverse of the coin happened within the first few minutes or so. Even after leaving it in there for several hours made no difference. I even used a Q-tip to help rub the paint off and what you see if the final product.
The thing here is you've already gone this far attempting to remove paint from that coin so no CENTS stopping now. As already noted there are some epoxy type solvents on the market. I still would suggest an attempt at Laquer thinner. As I've noted you could leave that coin in Acetone for 20 years and possibly nothing else would happen. Prior to spending money on products that may not work, I would suggest attempting to further try items possibly already present. For example a little Gas from your car. Fingernail polish remover, basically Acetone though. Denatured Alcohol. Or if make a Martini tonight, try some of that. If you are into Martini's you may forget all about that coin's problems.