I used the mother's headlight restore kit a little while back, i only had to do it again recently because the first time i tried it i had no clue what i was actually doing expect apply and thats it. they stay pretty clean for a long time, i drive on a lot of back country roads a lot so they get put through the test of staying clean.
Ive used all diferent kind of kits and they didnt work for me. Surprisingly I already had the tools to do my own restoration without paying for kits. This is what I did: I water sanded my headlights with 2000 and 1500 grit sand paper. Then I buffered the headlights and put a 3M sealant over the headlights to prevent further hazed/fogged lights. If you have a buffer id say do this method as sand paper and 3M sealant isnt costly. It took me about two hours, and yes, your arms get tired. But after being fed up with the kits it was worth it. The results were instant and Ive not had a problem since and its been a year. Hope this helps.
Sorry, I was hastily looking through my father's garage because it wasn't in mine. He gave it to me. The bottle was old and looked to be from the 1990s but was never opened. Also, what i meant by sealant was that I added a clear coat on the head light, probably can get it at Wal-Mart/Lowes/Home Depot. Like I said, its been a year and no fogging/hazing has reappeared. I recommend that you do this.
Get the sylvania kit, it comes with the UV clearcoat that prevents the hazy yellowing from reappearing. I spent about 3 hours on mine, and they turned out pretty good. Not brand new looking - just very slightly cloudy, but since the car tends to show its age a few places it looks like they 'belong'.