How did you get your turning signal lamps so clean? what did you use on them?

 

Well... I've done tail lights with a medium compound, then a fine compound, and that worked. I've done headlights (see picture) and we sanded up to 600 grit, wet sanding, then used a medium, then fine compound.

IROCKER was mentioning using a metal polish as well.

These headlights were a typical ford faded yellow garbage. We sanded them with 180grit on a D/A sander, then sanded them with wet sand paper up to 600, then used the medium and fine compound on a buffer at around 1500RPM. Check the results

 

Hey man...this is what I posted in another thread:

The trick to clean up the lenses is quite simple...

1) Remove the lenses from the car...this will make it much easier and you'll have better results.
2) Using some metal polish (I use Mother's...but other's like Autosol will do) scrub down the outer surface of the lense and then buff it. Do this a couple times and you will notice right away how they start to clear up.
3) Now using 1500 grit (no less!) and lots of water, wet sand the lense. This helps to smooth out the pits and fine scratches. Don't be alarm when the lense dries off that it's all foggy / cloudy again...we'll get to that part.
4) Now using 2000 grit and lots of water, wet sand the lense again. This step is necessary to get rid of any of the fine swirl marks left from the 1500 grit.
5) This is the hardest part, cleaning inside of the lense. You can break open the seal and separate the lense from the turn signal housing, this would be the most fool-proof way, but you do lend the risk of crack the old brittle plastic lense. If you want to open it up, that's your choice, just be careful. What I did was pour in some Simple Green and hot water and let it soak. Then rinsed it real good. It didn't get all of it out, but most. If you can think of a better way then please let me know.
6) Now once everything is dried, it's time to clear up the sanded cloudy lenses. I strongly suggest the use of a three step process, whether it be Mother's or Meguirs'. You will need the pre-cleaner wax, the polish/sealer, and carnuba wax. Do the three step process as if you were waxing your car. The lenses will turn out almost completely clear once you've complete the three-step stuff.

That's it. They won't look as good as brand new ones, but for only a couple dollars of materials, they will look 100% better than before.