Removing corrosion/oxidation from alloy motor covers

What sort of dremel bits have you used? Used to do it all by hand but wanting to use dremel now. Tried sanding drum bits (too scratchy). Metal wire brush bits work ok, but Im wondering if there are better bits to use?

soft wire brush and then a polishing mop but what do I know. Most of my casings are white and furry  

Found a guy in Te Atatu Peninsula that has every dremel bit imaginable and is cheaper than Mitre10. Testntools.co.nz

Is that in the villiage bit?

Left at the village roundabout, right onto Matipo, left onto 9 Renata.
All the stock he has is listed on his website. I have had to play around with a number of dremel bits to get a system.