dirty headlight lenses

I just bought a '98 Taurus SE w/ 76k. The headlight are really dirty on the inside of the lenses. How should I go about cleaning these?

Thanks,

Goose

Wet sand with 600 grit then sand with 2000 grit(takes about 5 minutes)then buff with autosol or any metal polish for obout 1 minute and thats it. They look brand new!!!!