Its not on the inside of the headlight the yellowing is on the outside, do to the sun and heat. Get yourself some Turtle wax the polishing compound kind and go to work on the headlights. Use a rag to apply the wax in circular motion and let it sit for like 3 or 4 mins and then with a clean non scratching rag take off the wax and then get back to me, LOL!! make sure the wax is the polishing compound it should be maroon color. Oh and you'll probably will have to do this to the lights acouple times to actually get them looking new. And make sure you dont get the compound on your paint.
