I have done quite a few light polishes the past few years on various cars. I would recommend wet sanding the headlight use plenty of water. Start out with like a 600 grit and work up to 2500 or even 3000. For polishing compound i know people will probably hate me for this, but i use mothers mag and aluminum polish. You can use either a cordless or corded drill and a3 or 6 inch buffing wheel. I picked up my buffing pad at harborfreight for 3
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https://www.harborfreight.com/6-inch-polishing-kit-66713.html just smear a little polish on the lense and buff it off. They look like new after.