Thank you! It's just the process of polishing aluminum. You need to strip it from paint and then sand all the imperfections from the surface of the aluminum. Once all the imperfections are removed then you sand the surface with 220 grit sandpaper, then you use a buffing wheel and polishing compound to get the shine. Here's a link to a Youtube video where a guy is polishing a fuel tank and takes you through the steps:
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