Just looked at the Napa Aluminum Brightener and want to give you all a tip on saving body parts. This cleaner contains Hydrofluoric Acid, this is not like regular acid, it adsorbs into the body and eats tissue by replacing calcium.
Now that said, it is in a concentration which is not immediately a big issue, but you should definitely use gloves and keep this stuff off your body and out of your eyes (don't overspray, spray into the wind, touch it and then wipe your eyes or eat or smoke/chew).
I just got my kawi a month ago and have been looking to find ways to clean up the aluminum because I see how good everyone's quad looks on here and mine has the typical soil staining (soil in PA is mostly acidic and always stains open pore aluminum and soft metals easily). I work in facilities and safety for a research facility and this chemical is used widely in research, but it is the most feared/respected of all the acids. Does not immediately burn, but after working on tissue and can get into bone marrow it starts a throbbing pain and leaving whitish tissue.
So long winded story aside, just don't screw around with this stuff...
By the way I am picking some up tomorrow at the local NAPA so thanks for the info...