you can remove the corrosion with scotch bright. and etch it Aluma Prep. It is a acid bath to kill any corrosion left behind. On aircraft we take it a step further and Alodine the surface. This is a chemical conversion coating but it will leave the bear spots a gold tint, much like grade 8 hardware. Your best bet would be to clear coat the repair with a polyurethane of some sort. any body shop could spray it. Other than that???? not sure??? Anodizing is like electroshock therapy, so reproducing the coating would require having the whole thing re finished. Hope this helps