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I had a similar issue with somebody else's over exuberant use of styrene cement and - no guarantee it will work for you but - I spotted advice to stick the body in the freezer then have a go at it. 

It certainly helped me with shaving it away using the sharp edge of a new craft knife blade BUT I wasn't trying to preserve original paint. I wanted to get back to  the bare plastic anyway. It WAS a case of of being very patient and careful though, as I didn't want to damage the surface of the plastic itself.

Good luck, however you choose to do it