I'll be applying this method on the rest of the applicable bike bits - steel and uluminium but not chrome. Lightly buff surface with a sanding wheel in a drill to remove the corrosion and smooth out pitting, follow up with hand applied 1000 grit sandpaper and then 1200 grit in a single direction(not circles) to remove the sanding wheel marks, smooth out any residue with fine steelwool, this still leaves the surface dull, I wipe on Autosol and then shine it up with a cloth buffing wheel in a drill, the wheel is like 15 slices of denim stuck together and I got it at Builder's, Autosol from Midas. Lots of work but well worth the effort.