always remember to take off your WWF Championship belt before a gig

Is it scratched to the wood? You can dab some black fingernail polish there and sand down with progressively finer grades of sandpaper, then polish, etc., but if it's on the back of the bass I wouldn't bother with it. The finish will always be slightly uneven spot treating in this way unless you have repeated-sanding patience the size of Oprah's butt. As an absolute last resort you can start wearing elastic band Dockers instead of riveted jeans (not a good option for those under 50).