Forgot to mention to use a spray bottle of water with the toothpaste. You could use rubbing compound too. I think that's what in the kits. If you ever colored sanded a car (wet sandpaper) it's the same thing.
Stop by a paint store and get the 3M. You can do a dealership lot with the amount they give. For jacked up lights start with red compound then work with the lighter stuff. Carry it with you because people will stop and ask about it, you just made back your $20 bucks. Cleaner wax works in a pinch if lights are not bad. The 3M works on plastic windows as well. I tested on windshield scractch and took most of it out.
The headlights on my Durango were extremely yellow and there wasn't much of a difference between my low-beams and high-beams. I was out shopping with my girlfriend one day and came across a bottle of Blue Magic headlight lens restorer. It was $6, so I figured, "why not?" I applied the product using a microfiber cloth and wiped it off with another microfiber cloth. It took several applications until my headlights were noticeably brighter and clearer; there was a slight improvement in low-beam vs. high-beam. They're not 100% and definitely not as a clear as the turn signal lenses but it's a definite improvement. The directions also call for for an application of Blue Magic headlight sealer. I didn't bother to seal my headlights since the store I bought the restorer from didn't carry the sealer.
Anyway, it's been about a month and the lenses are starting to turn yellow and hazy again. I figure I'll clean them up this weekend when I change my oil. All in all, for $6 it's not a terrible product by any means but it doesn't restore the lenses to brand-new condition. The next time I'm out I might pick up the Meguiar's treatment or possibly the Rain-X, and I'm definitely going to spring for a set of Sylvania SilverStar bulbs (which should provide a major improvement with my low and high beams).
Go 3M and a buff ball. I have the one piece and they have yellowed and begain peeling. I have a Mothers small ball but they all work the same. Charge beer money to friends and it pays for itself. I have done most of the neighbors. Funny thing is people are doing this at the store now. 3M is what most detailers use.