You can ask somebody to clean the rim thoroughly with a rust converter or a rust remover chemical, then buff it until it shines, then wash it with a mild detergent to remove residue of the buffing chemicals like rubbing compound, then dry it with a clean clothe then spray clear coat (any car painter knows what clear coat is) this will preserve the luster of the rim and prevents any future rust.. now if it is the brake drum you are talking about, what you  can do is just apply a rust remover apply it with a steel brush, brushing away the rush, then wash the brake drum with a mild detergent, rinse it then dry it with a clothe before painting it with any color you like (use a paint for lead)....hopes this will help.