Just go down to a local auto paint store and buy 1 sheet each of 2000 and 3000 grit sand paper and some buffing compound. It's a lot cheaper than the kit and is the same thing. Wet sand them and finish with the compound and a rag if you don't have a wheel. You'll have to keep them waxed after that, though, because you'll have removed the hard factory finish, which just happens to be the part that turned yellow. The polishing won't last as long as the original shine. You might have to redo them once a year or so.
That said, it really shines them up, removing all the yellow that kills the light. It worked great on my pickup. However, I was going to do it on our van but the haze was on the inside and impossible to get at. I got replacements on Amazon for something like $30 each. They're a couple years old now and work great.
