You may want to go as far as wet sanding it with 2000. I done mine earlier today. Whatever you do, dont use acetone. Maybe fingernail polish but not straight acetone. Yeah the acetone will clean the yellow stuff off but then it starts to eat the plastic and your lenses will be more fogged up than before. I finally got mine looking decent. First I had to use 600 to fix the plastic that the acetone funked up then I worked my way up to
2000 and wet sanded. You will really start to see a difference when you use the polishing compound. I used both the 3M stuff and the Meguiars Plastx plastic cleaner and polisher (Meguiars a little better). They came out better than before but they are not perfect. Tommorow I am going to use the buffer I bought from Wal-Mart maybe that will help a little bit. I would suggest you to use the polish first before you started sanding anything maybe to save yourself some trouble.