Oh trust me THEY ARE Alcoa aluminum 99.99% of the time. Not clear coated, polished. Ran those puppies for 18 years, know them WELL.
:whs::dblthumb2:
I know a guy here in town that was getting his big 60 ton rotator ready for a show. He asked me what I used on my trucks (way back when) as I always took 1st place in rollback division EVERYWHERE we went.
Based on our conversation, he went out and bought a new rotary with a cotton buffing pad, and a TON of jewelers rouge sticks. Now he had not 2, but FOUR 150 gallon tanks on his rotator, plus all four axles had Alcoas on them. He spent THREE DAYS polishing aluminum!
You want to save TONS of time getting the entire undercarriage totally clean?
Get several gallons of
hydrofluoric acid-based aluminum brightener.
DO NOT USE IT FULL STRENGTH!!!!
You can, in certain, HIDDEN PLACES use it full strength, but I'd be EXTREMELY careful. It'll etch paint AND GLASS. It'll severely dull aluminum as well.
Put it in a plastic pump sprayer (or a stainless steel one), and dilute it.
You can dilute it from 1:1 up to 3 parts water to 1 part acid for cleaning the frame. Spray it on a dry frame, inside and outside the rails, DO NOT let it dry, then go back and rinse, rinse, rinse and RINSE. I'd suggest rinsing the first and second time with a pressure washer. Then go with a hose and get maximum water on the surface.
COVER ALL TANKS, POLISHED STAINLESS AND WHEELS!!!!
While it can be dangerous, it is a fantastic frame cleaner.
DO NOT GET DOWN WIND!
Use some sort of respirator for lung protection. (It will reach inside your lungs, grab the very bottom, then pull it inside out whilst twisting and jerking till you think you'll hoc up a kidney!
What it will do for you though is make the frame so clean it'll look like you went over it with a toothbrush inside and out.
All that aside... any acid based wheel cleaner will likely be hydrofluoric. It just makes more sense to buy it straight, by the gallon, then dilute it to your needs. You can also add APC to your pump sprayer and make one heck of a nice 'home brew'. Just be VERY careful with fumes.
You can use it on wheels and bare aluminum, but you'll want to dilute it more like 20:1 AT LEAST.
These days I much prefer non-acid wheel cleaner on all wheels. Although... I've cleaned Alcoa wheels, lots and lots of them without any damage with my 'home brew'. The key there is a safe dilution, and wetting the wheels first, as well as KEEPING them wet if you are working with an acid based cleaner.