I have a matte black wheel that sat in front of a sprinkler for the past 9 months while I was in Afghanistan. Attached is a pic
I have tried 50/50 water/vinegar, compound, SSR2, and clay and nothing has really touched it. The compound helped a little, but the etching is still there. Is there anything that can help facilitate cleaning this better? I applied all polishes by hand, buy maybe using my PC would help? Again, this is on my wheel, so that would be a massive pita. You can see at the bottom is a small area that i used the compound on. It shined it a little, but the spot etching was still present. Any help is appreciated.

I have tried 50/50 water/vinegar, compound, SSR2, and clay and nothing has really touched it. The compound helped a little, but the etching is still there. Is there anything that can help facilitate cleaning this better? I applied all polishes by hand, buy maybe using my PC would help? Again, this is on my wheel, so that would be a massive pita. You can see at the bottom is a small area that i used the compound on. It shined it a little, but the spot etching was still present. Any help is appreciated.