I think they make some form of finishing for clear plastics (Lexan, acrylics, plexi) I saw a pretty slick tutorial on cleaning and polishing a pinball machine. Im pretty sure its the same deal here they make a few step process to remove scratches (prep. apllication. clean). Im sure someone here has the info you are looking for. I myself have never tried it but I guarantee you can get that DK bezel looking good! While listening to some blue oyster cult that is (joke on your username)
Neil