I can't believe this worked but I have an old 97 SC300 that I refuse to sell regardless of what my wife says. I was getting annoyed with how dirty the old headlights were and was considering buying new ones just because but saw a fb post that changes everything.

DEEP WOODS OFF. That's right. Drench an old rag with deep woods off or any bug spray that has a good amount of DEET in it and it polishes right off. I couldn't believe my eyes. I didn't even rub that hard and it came right off like new. I almost bought a sander for it but no need. Try it.. Bug spray costs $5.

 

Any abrasive will work.
DEET is abrasive, so is tooth paste, so is polish.

You can do whatever you want, just tape off the surrounding paint so you don't dull or swirl up the paint around the lights. I prefer using several cutting compounds to do it, but that's just me DEET and toothpaste work fine for light oxidation.

 

I prefer glass headlights...

For the plastic ones I've found wet-sanding, followed by cutting/buffing compound, followed by polishing compound, and topped off with a plastic safe polish yields the best results. Have taken many yellowed and hazed headlights back to crystal clear, of course this has been on family and friends vehicles seeing as every car I've owned so far has had glass headlight covers. I've also never owned a car made past 1995, but that's ok too.