Redo 1970. Depends on how deep the scratches are. If they're really deep I start with 80 grit or even a fine tooth file. If they're not real deep, 180 or 220. I use wet and dry and a spray bottle of water with a few drops of dish washing soap added. I work up from 80 to 100, to 180, to 220, to 320, to 400, to 600, to 800, to 1000, to 1200, to 1500, to 2000 and finally 3000. Then I start the buffing. When I'm done it shines almost as much as chrome. Lots and lots of work and time. It took me almost three full days just to do the windshield trim. Definitely my least favorite part of the restoration.