FYI. I deal with a lot of powder coated aluminum. We do a lot of powder coated aluminum decking for decks, balcony's etc.. I had a customer that was using a "purple cleaner" to clean with and getting black spots on the deck. The product was "Heavy Duty Spray'n Wipe". It's a private label cleaner so no major brand names for it. I tested it over a week. The photos are at 100% concentration over 4 days. I also tested at 10% and it wasn't this bad but was heading in that direction. Aluminum is 6005A-T6, pretty identical to 6061-T6 with a AAMA 2604 powder (2nd high architectural rating).
MSDS for it:
111-76-2 Ethanol, 2-Butoxy- {Ethylene glycol n-butyl ether, Glycol Ether EB} 3.0 -7.0 %
1310-73-2 Sodium hydroxide {Caustic soda; Lye solution} 1.0 -5.0 %
6834-92-0 Silicic acid (H2SiO3), Disodium salt 1.0 -3.0 %
Looks to be real similar to the castrol superclean.
Severely ate into the aluminum and completely changed the powder color. I really had no idea this stuff was this rough.
I did a lot of testing with different chemicals on the decking and the safest and best working I found was the purple Krud Kutter Multipurpose cleaner. No damage or color change at 100% and cleaned a deck that was 8 years old at the back entrance of the facility really well.
Not sure how it will do on the Honda and I will test it sometime soon, if we ever get rain in Alabama again!
So, be careful with the cleaners and make sure you rinse them off very well if using a product with those chemicals around aluminum or anything powder coated.