Thanks! I put new assemblies in the XTerra,they were $150 each after market, but look and work great. I need something for the truck though as the replacements are a fair bit more.

Mother's mag wheel polish, cheap.

For protection I had clear bra film put on the plastic headlights of our new car, along with the whole front of the car. UV and sand / grit impact protection. You can get small rolls of it on Amazon fairly cheap. Hopefully it will last a long time and peel off and replace if needed. 10 year Warrentee.

For polishing my old car lights I used the rubber pad on my oscillating tool that is made to use with sandpaper on it. No sandpaper, I just put some automotive polishing compound on the rubber backing pad directly and buff away. I only had fine grit but it worked pretty good.
It would have been quicker if I had used progressively finer compounds I expect. I didn't coat the lens so they dulled again in a year or so.