My headlights were so dull one could not see the light bulb. For the daytime lights that was fine, but at night the frosted lens really cut down the distance of effective lighting.
I started out using Plasti-X and a microfiber cloth, which helped a lot. Yet a some point somebody had placed a coating of some sort on mine. Factory? I dunno but it was coming off and causing weird patterns in the beam so it had to go, whatever it was. I tried the no sand route with a few products none of which worked. Ordinarilly things like Plasti-X or Mothers wheel polish would probably do fairly well but my lenses said "pffft, got any other bright ideas bucko?"
Stashed in my trunk from another project was an older 3m no drill kit from when they came with 3 discs. First one being 500 grit. Now they have 2 discs, first being 1000 grit. I dry sanded whatever that stuff was with the 500 disk. Uh oh! Now they are really frosted. But the remains of that coating were gone.
Got out my spray bottle of water and commenced to rubbing the lenses with a new 3m kit. The 1000 grit rubbed up a nice slurry of yellow tinted paste. Wipe that off and by the 3rd rub down the yellow was gone. So then I did the 3000 grit. Low and behold I could see the light bulbs again. Afther the third rub down I could see "made inbJapan" again. Nice! Yet it was no gin clear yet.
I rubbed on Blue Magic wheel polish and could see light at the end of the tunnel was not a train. Wait about 10 minutes and buff it again and it looked pretty good. Then the last step was to apply the 3m supplied clear coat. They looked about as close to new as they ever will without using a drill. The 3m drill kit is amazing but I prefer to hand rub my headlights as one slip and you have a scratch on your car, even if using masking tape.
All told it took about an hour and a half to rub down all 4 lenses on my GS300 and get back almost new looking headlights. I considered keeping the DRL's frosted but opted not to.
Now by the 4th lens the disks were kinda worn so extra hard force had to be applied to get good results. If you look closly, the right side lenses are not quite as clear as the left side ones so I'd reccomend buying 2 of the 3m kits if you don't want to have to use a "scrub" amount of effort. The kit was $10.49 at my local auto parts store.