I have been experimenting with engraving aluminum with a V tip bit. I made a dog tag for my dog Snoop.
This is cut to a depth of .4mm with .3mm steps at 5mm/s. This was polished with a cloth buffing wheel. I cut it out with a jig saw, drilled the hole and filed the round edges. It was finished polished with the buffing wheel and then polished by hand.