Here you go. this was a knowledgebase post I did at 300mclub.org - Warning LARGE POST
Now Prices do vary But here goes.
List of Materials : Most things can be bought at auto stores
Corded Drill : You should already have one, If you don't, $30 from Homedepot
Spray Bottle with Water : Every home has at least one, if not $3
400 Grit Wet/Dry Sandpaper : $2 Only needed for heavily damaged lamps
600 Grit Wet/Dry Sandpaper : $2 Only needed for heavily damaged Lamps
800 Grit Wet/Dry Sandpaper : $2
1000 Grit Wet/Dry Sandpaper : $2 *Required*
1500 Grit Wet/Dry Sandpaper : $2 *Required*
2000 Grit Wet/Dry Sandpaper : $2 *Required*
2500 Grit Wet/Dry Sandpaper : $2 *Hard to find Locally*
3000 Grit Wet/Dry Sandpaper : $2 *Hard to find Locally*
Meguirs Or Mothers Plastic Polish : $5 *Required*
Polish Cloth, Pads, Applicators, Buffing Pad : $2-15
Total Without Drill $21.
You can save money by buying Bulk Packs. IE I bought a pack for $4.50 that included 1000, 1500, 2000 Grit sandpaper. Then another pack that included 400, 600, 800 for $4.00.
Now the polish applicator is the tricky part. I refused to do it by hand so I used a foam pad along with a drill adapter for the pad. I got it from a special Kit they sell for $5-10 dollars in stores. The purpose of the kit is to repair headlamps but the pads themselves do NOTHING. You can buy foam pads and the backing plate separate. The buffing pads are also nice to have.
Another product that didn't work was this. The polish in it was terrible. The kit MIGHT have worked if I spent more labor on it but I didn't. IMHO IT was a waste of money. $15
Also alternatively you can buy a kit like this.
It includes everything needed and then some. Much better kit(Scroll down, $40 dollars) You would probably get better results.
Now onto the meat and potatoes of this guide
Step 1. Choose your Starting Sandpaper. 400 Grit for Yellow/Heavily Damaged Lamps, 800 Grit for Ugly ones, 1000 For light damage
Step 2. Cut the sandpaper into a circle or square, Cut 2 Circles of each type. About 3-5" In Diameter
Step 3. Soak All your sandpaper in water for 15 minutes. Leave them soaking
Step 4. Either Tape off around your headlamps(Good) or Remove headlamps from Car(Best)
Step 5. Wipe Headlamp with mild cleaner (Windex, Soap) Dry with paper towel
Step 6. Take starting sandpaper(400-1000 Grit) Spray Headlamp with water from Spray Bottle and begin to sand Lightly. Every so often spray the headlamp and continue sanding, Every 2 minutes or So dump the sandpaper into water, shake it clean then continue. Sand for 10 Minutes. Go Slow and do it evenly. Focus on the bad spots but don't OVERDO it there. If it's badly yellow you might need more time here. This step must be done with care as it's the most abrasive. If you screw up you risk making a indent in the headlamp, weakening it and causing it to break.
Step 7. Wet the headlamp, Wipe off with cloth or paper towel.
Step 8. Move up to next grit size (400->600, 800->1000, 1000->1500) Depends on where you started and what sandpaper you have, Again continuously wet the headlamp and start Again, Sand for about 10 Minutes Always wetting/wiping. I used circular motions with my sandpaper.
Step 9. Wet the headlamp, Wipe off with cloth or paper towel
Step 10. Move up to Next Grit Size(600->800, 1500->2000 And so on) Sand and wet for 10 minutes.
Step 11. Wet the headlamp, wipe off with cloth or paper towel
Step 12. Move up to the Next Grit size. For some this might be the last size (2000+ grit Is a good stopping point, 3000 grit Is better but harder to find)
Step 13. Continue Steps 11-12 Till you reach the highest grit size you have
Step 14. Wet the headlamp, Wipe off with a cloth, cotton, microfiber towel. Headlamp will look cloudy at this point. When you wet it should look clear
Step 15. Take buffing pad and buff headlamps out. If you're using a drill do it for 5 minutes till you see no sanding marks. Doing it by hand, 10-20 Minutes or more. *Optional Step, Better Results if you do it*
Step 16. Apply some Plastic Polish to a foam/microfiber pad. Slowly work it into the headlamp little by little. If you have a drill this becomes easy/fast. Continue to add more and more polish. The headlamp should start clearing up. Continue on adding more and more polish. Not A Lot. The headlamp should be clear sans some polish. GO SLOW. Do this at low RPMS and don't press down hard with the dirll if using one.
Step 17. Wipe headlamps off with terry cloth, cotton rag, microfiber towel.
Step 18. Reinstall Headlamp or remove tape enjoy the nice looking headlamps
That's it. Now because of how our cars cab forwardness fronts they will turn ugly again. Think about investing in some headlight protective film to combat that. Or Redo the polishing steps every 2-4 months or so.
Now for a Picture Walk-through of What I did and used.
Here's Everything ready to go
Closeup of the polishing pad, The backing and pads came in a kit that cost me $5 dollars, I normally see it for $10. They sell it at walmart and most car stores. It came with 6 Foam pads and the drill backing adapter.
Starting off harsh. This headlamp was yellowing. 400 Grit!
Polishing Step 2 Shot of the drill + pad
And now for the result. Here's Before
Here's the passenger side done, and the drivers still ugly
Here's both done.