I was planning to paint my rear muffler matte black to hide the ugly orange marks until the boss lets me get a new exhaust. Before painting it I decided to see if I could clean it up with sandpaper and some exhaust polish. I'm quite pleased with the results. It still could use a bit more sanding inside the grooves but it started raining so I had to call it a day. No paint needed.
///M3 E92 SSII