Problem sometimes is that some corrosion can get under the anodizing and you cannot really take the finish damage off the component unless you strip the anodizing off and polishing the bare aluminum. Bet there are cases where the finish damage is on the surface, on the layer of anodizings. It is usually har do take of shopwear or riding nicks and scratches on such because of the very hard nature of the anodizing that does not really take to polishing with compounds and cleaners that well, but I did discover this last winter with two of my cranksets, that you can remove most of it with a good amount of elbow grease and the mildest of polishing compounds. The trick is to be careful not to polish out the anodizing all together but polish it enough to get most of the scratches and marks you are trying to eliminate. It won't be 100% perfect, but you'd be surprised how much you can take off and still maintain the anodizing on the component. I save a few NOS components already since that first one that had a bit of shopwear on them and they now look NOS after my careful cleaning.

Chombi