Contrary to what many people believe, aluminum actually can rust. Cast aluminum is a denser form of aluminum that has some of the properties of aluminum and some of the properties of light-weight aluminum. Cast aluminum is used for furniture, cars and other metal objects that need to be tough and lightweight. Over time, exposure to air and moisture will cause the aluminum to corrode. You can remove and repaint the metal to prevent further damage to the metal and to make the metal usable once more.

...
Many car wheels are made from cast aluminum.

Step 1

Put on a dust mask and eye protection to prevent inhaling metal dust and to prevent the dust from getting into your eyes. Spray the metal with a spray paint remover designed to remove paint from metal. Allow the remover to sit on the aluminum for about 10 minutes. Wipe away any remover residue with a soft cloth.

Step 2

Sand the entire surface of the cast aluminum with the rust-removing sanding pad to remove all signs of corrosion and rust. Allow the aluminum to sit overnight. The paint remover will remove any paint and rust from hard-to-reach areas overnight.

Step 3

Sand the metal with one final set of sanding using a fine-grit sanding attachment. Wipe down the surface of the aluminum with a damp cloth to remove paint and metal dust.

Step 4

Spray the metal with an aluminum primer. Allow the paint dry for two hours, then apply a second coat of aluminum primer. Allow this coat to dry for two hours as well.

Step 5

Spray the aluminum with the rust-resistant paint. Paint a total of about three coats of paint onto the metal, allowing each coat to dry for at least an hour between coats.