normally for copper the best is to soak it in olive oil it'll take a few days, then clean in water. I usually bring a vial (or medicine pill bottle) of water to immediately put the coin into water to soak. The problem is that when the soil dries off it turns to concrete. So, keep it wet until you can clean it properly.
The key to soaking it in Acetone is the length of how long you have done it. I have soak trial coins in there for 1 minute to 48hours to see what the effects are. Lemme tell you, more than a couple of minutes will be destroying the coin. At least in my experience