What can I use to clear the yellow build-up from my headlight lenses?

Wet sand with progressively finer grades of paper up to about a 2000 grit, then polish with a plastic compound.





Permatex makes a kit for that job. The easiest thing to do is replace the assemblies.What can I use to clear the yellow build-up from my headlight lenses?
I have used a product called ';CV Headlight restorer/defogger';


Found it at wal-mart in the section where they sell replacement headlight bulbs. Cost $20 which was cheap compared to the $140 for new headlamp fixtures (each!).





Took about 30 minutes, easy to do. First car I did about 6 months ago and they still look good.