I purchased a heat-gun earlier today from Lowe`s (Homebright Heat Pro Plus in case anyone is interested). I`ll test it out first on one of my Compact Mac cases tomorrow (the 128k upgraded to a Plus with the BNC adapter installed - that one is in pretty rough condition internally - and somewhat cosmetically. But I couldn`t careless about that one at the moment), and see if the heat-gun route works out (this particular heat-gun model comes with a deflector nozzle, which should make focusing the heat on the scratched areas a bit easier).

Naturally I`ll remove the rear-bucket case from the rest of the unit before experimenting with the heat-gun.