Originally Posted by Chombi

Buffing out a crank does take a lot of elbow grease and time as there are so many nooks and crannies you hae to hit. You can do a mirror, chrome-like finish on them , but I think a satiny finish with directional grain looks so much better. Trick is to get it as polished as close to mirror finish as you can, then you hit it carefully with gentle directional swipes with fine Scothbrite pads. If you will look at NOS cranks, this finish will match it very closely and sometimes even look better as you are in control of how you apply the "grain".
BTW, If you do buff a crank out, Make sure you do not create any stress risers by grinding and polishing the material down too much and creating very thin edged corners anywhere on the crank where stress cracks can start propagating. Buffing/polishing the crank will also give you the ooportunity to knock down stress risers edges and corners that the factory originally left on the crank.

Chombi