I recently had to get 2 new tires installed, I took my car to a tire shop that installed them ,as soon as I got home I noticed they had sprayed something on them that stained my rims!? A day before a show !,and wouldnt polish off! ..,but not too did some research and decided to try the "acid wash" on polished aluminum. As some say never to do so!..I did it lol diluted 4.1..I sprayed acid for about 45sec.you can tell when it working it turns into white foam .rinse with water and it turns into a foggy look.(like u ruined the rim)..then all you gotta due is polish! Them (I used blue magic polish)..and bam! Looking like new!..and that's my 2 cents of a rant for the day ...