If these pieces are stainless steel the scratches will come out starting out using a lower grit number sandpaper than 3000. I polished a grill piece on the ‘37 and it was in much worse condition that the one in the photo. It fact, it even had dents. A friend loaned me a tool he made that raised the dents. These were then filed flat, yes a file and yes there was stomach turning horror when he demonstrated the technique on the piece. Once I completed that step on all the dents, we moved on to using progressively finer grit sandpaper. The grit started at 120, 220,320, and on up to 600, then we switched to brasso, then a solution that had an even finer grit. I don’t recall off hand what that one was now, I got at a swap meet years ago. I think now I’d likely use several different progressively finer grit papers body shops use, instead. This grill piece turned out looking pretty good.
Good advice . But if you have just light scratches then I would start with 600 or above . Work up to 1000 1500 and 2500 . Then if you have a compound set with cotton wheels it will polish to a near chrome finish. Never quite as bright as chrome but close.
