Returning Aluminum to a near "Mill" finish

Our company produces aluminum tankers for the gasoline industry and about half of our tankers have a polished surface, while the other half are of a mill finish. My question is this, if scratched the mill finished tankers require an amount of sanding and polishing to remove the scratch or blemish, what if anything can be done to return the polished area to near the original mill finish look? We have tried several things and have gotten close but have yet to find something which mimics the mill as closley as we might want. And anodizing is not an option as the industry standard is to either paint the tankers or the more preferred is to leave the tankers in the original bare aluminum.

Suggest you try a non-woven wheel or belt system. The trick is to not rotate flat against the surface and try to go in the direction of the grain. The fether out the edges. If you apply too much pressure yu will get a polished look. If scratch is too deep, then you may have to use a 2 step process and reguire a more aggressive grit first.