If it is the outside part of the rim you may be able to remove the
rust with very fine steel wool.  If the center section is pitted then
that is usually made out of some sort of cast aluminum and the only
repair I can think of is re-chroming the piece.

                             ...Ron
--
68' RS Camaro
88' Formula Bird
00' Mustang GT vert
http://www.frontiernet.net/~rscamero

Some are wise and some are otherwise