If it was polished under the paint and you planned on polishing it later, you can use aircraft stripper. Most are methylene chloride based and if washed thoughroughly with water then soap & water after most of the residue is stripped off, there should be no structural problems with the aluminum. Some aircraft strippers have acid mixed in there to allow epoxy and polyurethene paint removal. These would have to be neutralized during the wash process. The kind you buy at the hardware store is mostly methylene chloride. I've stripped quite a few airframes and have not had much problems with strippers around forgings & castings as long as you don't leave the stuff on there too long. Plastic and fiberglass are the ones you have to cover real well. It sometimes takes repeated coating & rinsing to get all the stuff off. Good sense prevails on these jobs. We have to reseal all joints after stripping an airframe. It's a messy job and not much fun.
Walnut shell and plastic media blast does a pretty good job but has a hard time with stubborn paints. You will likely need to take some progressively finer Scotch brite pads and polish to the sulface and maybe some 400 grit aluminum oxide paper on scratched areas anyway prior to final polishing with buffs & rouge.
