wet/dry paper with water all over to start. Panel at a time, very time consuming around the rivets.
320 If the vault was scratched up
800 800/1200 preferred starting grade depending on vault condition.
3000 soft pad to finish.
polishing i used a angle grinder with ‘dronco’ flap disc and ‘white soap bar‘ metal polish.
found 2 good passes on each panel worked well.
Then around all the rivets i used a dremel with a polishing pad and autosol polish cream.
final hand polish all over to make uniform finish..
im no expert and basically used stuff from work / had in my garage. The metal polishers on here probably have better tools / work routine but happy as a first effort. Its a learning curve