buffing wheels are ok if there's no scratches. I polished up a home made aluminum shroud I made for my dad's van. started with some nasty scrap yard, heavilly oxidized aluminum, and started sanding with 180 grit sand paper. kept stepping up in grit...220, 400, 600, 800, etc. all the way to 2500 grit paper, then hit it with a buffing wheel and it came out looking like a mirror.

like a good paint job, it's all in the prep work before the buffer ever gets turned on