We have a mixed set of cranks on the tandem being, three CPi cranks (two for captain and left hand for stoker) and a stronglight triple crank (for the stoker). We are in the process of "rebuilding" the tandem. There were some scuff makes on the Stronglight crank. I sanded the crank with 800/1000 and 1200 grit carborundum paper and polished the aluminium alloy with Brasso. It ended up looking much better than the crank originally was. The CPi cranks looked like it was a brightly polished aluminium alloy. I thought sanding out the scuff marks would be easy. It now seems that the cranks has some coating (chrome??? or anodizing) on it. I seems that I now will have to sand down all three cranks to obtain similarity, a very labourious process. If it has a coating would it be ok to leave it uncoated or would they wear down??? Can I stop where I am now and have all three anodised??? Is there an easier way to get rid of the anodising or chrome???? Help and suggestions would be appreciated.