I thought mine were beyond saving because they were black as coal but after 2 long hours they turned out great
I put on 2 pairs of disposable latex gloves here because you’re dealing with some nasty stuff.
Products:
1. Alloy Cleaner
2. Brake Cleaner
3. 600 grit sandpaper
4. Brillo Pad
5. Cloth
6. Einszett Metal & Chrome Polish
I started by letting the alloy cleaner sit on the exhaust for 5minutes to ease off some of the stuff.
I then sprayed it liberally with brake cleaner and gave it a good going over with the brillo pad which I have to say did most of the work.
The burnt on bits that wouldn’t come off were attacked with a combo of wet and dry sanding.
Finally the chrome polish was added to the sandpaper and went at it again.