Was trying to get the black mark off my xmxx by washing it with soap, using cleaning cloth and my dremel with the cotton wheel but couldn't get the black marks off. Gave up then I remembered that I have a Brasso metal polish. Was really amazed by how it "cleaned" up my pair a bit.
Before:
After:
Still has a long way to go to get to look brand new, but really happy about the results
Before:
After:
Still has a long way to go to get to look brand new, but really happy about the results