While cleaning my car the other day and trying to get yellowing off lenses, after trying all the different pollishes and cleaners I had, I noticed a liitle product I had not used in years call "GEL-GLOSS" its a fibergalss, marble and acrylic cleaner. I thought I would give it try on those yellow lenses, and to my surprise it took the yellowing away and I didn't even have to rub hard, I dont know if they still make it but if anyone is interested I will post all the info I have. Good Luck.