Hi! Just registered today...
I polish out headlights all the time...a whole lot cheaper and easier than replacing them...the new ones will eventually git dull, too.
I use the Mother's Powerball, an electric drill (corded works best), and some polish. I use anything from Mother's PowerMetal polish, Novus 2 plastic polish, to
Meguiar's PlastX... I just noticed that Mother's has plastic polish (PowerPlastic) made for hard plastic...like lenses. I used to polish the lenses by hand and it was a lot of work! Power is better! The Powerball costs about $20 at Walmart; PlastX costs about $7 at Checker Auto.
The alignment nubs on the lens might have a tendency to beat up yer Powerball a bit...
The key here is to take yer time and not to heat up the plastic headlight from the buffing. I use a liberal amount initially and using a slow speed on the drill...back and forth across the lens. Slowly build up yer speed and control until you work the lens for about 2-3 minutes. Buff off the residue with a soft cloth and presto...an almost new lens. Do this one more time and you probably won't notice the difference between a brand new lens vs the one you just buffed out.
If you want to protect the paint on yer hood, just lift it up and put up the support. It's better than trying to mask it off.