Great info thus far- makes this a good reference thread
Warning
Before using any chemicals or solvents, carefully read all of the cautions and medical information on the products container and / or MSDS. There is a very fine line between effective cleaning and dangerous to use products; always follow all of the manufacturer’s recommendations. Ensure that you wear eye protection and acid-proof gloves; this is mandatory. No matter how safe an acidic product is advertised, never run the risk of it splashing in your eye or it permeating your skin.
See also-
Wheel Cleaners-
Wheel Cleaners:
Acid wheel surface damage -
Boxster Wheels looking grim - Detailing World