Anodised wheels are made from alloys that have been treated with a process that coats the wheel with a special material. Anodised wheels have been offered on high-end cars as well as on the aftermarket. Many vintage Porsches, for instance, came with anodised wheels. Anodising is a very hard coating that is superior to many other coatings such as powdercoating, but it is very difficult to remove stains from anodised wheels. As such, it is important to regularly clean anodised wheels.
Rinse the wheels thoroughly with a hose to remove any loose debris or dirt. Do the same to the wheel arches and behind the wheels so that no dirt or debris will fall on the wheel during or after cleaning.
Spray on a high-quality wheel cleaner like P21S or Mothers Wheel Cleaner. Scrub the wheel gently but thoroughly with a soft-bristle wheel-cleaning brush. Clean the rim, the centre and between the spokes.
To remove more stubborn stains, use a high-quality, mild wheel polish like Mothers Mag & Aluminum Polish to polish out the stains. Apply the polish with a clean rag and gently buff out the stains.
Dry the wheels thoroughly with a clean, dry, lint-free detailing towel. After the wheel is dry, you can apply a very thin layer of petroleum jelly to the anodised surfaces to protect them from stains. Rub the jelly onto the surface with a clean rag.