You just have to replace them. 3M has a plastic cleaner but it only works on the outside.
Its just cheap plastic Ford used, not just Mustangs but all Fords.
Yeah, I remember reading somebody posting a multi-step process of sanding off the junk. Since mine were also looking pretty nasty around the weatherstripping, I took easy way out and bought a nice clear set on eBay.
I posted a tutorial I made for when I did my headlights .... I'll post it again for those who want to clean their HL's.
If you follow this procedure you will be amazed!
You will need:
- 800 grit wet-sand paper
- 1000 grit
- 1500 grit
- 2000 grit
- Some 3M polishing compound
- Another polish you like
- Some time!
The procedure:
- Clean headlights first with soap and water (dishwashing detergent works great to get as much bugs and crap off as possible)
- Wet-sand in the order that I listed above. Start with 800, 1000, 1500, 2000. The key is to use a lot of water. Keep the sandpaper wet while you sand, this is very important.
- As you start to wetsand the headlights, you will say to yourself "damn I am scratching these things up" ... and you are. They should get more and more hazy and after the 2000 grit they will be super smooth but stupid cloudy. This is OK! As you WET sand, you will see some milky looking water .. this is just the crap coming off your headlights. You basically want to smooth the surface by sanding in one direction (back and forth) only. Each stage of sandpaper will make the surface more and more smooth but more cloudy as well. Once you get to the 1500 and 2000 grit, your goal is to WET sand using a plenty of water and you should start to see the headlight get clearer while sanding with water. So, when the headlights are dry, they will be hazy and smooth. But when you are wet-sanding they will appear very clear (especially when you get to 2000 grit). After you have done this, let the headlight dry, or dry it off in the same back and forth direction that you sanded in (would not want to scratch them at this point.
- Now is when the magic happens!! Get out some 3M polishing compound, polish on - polish off and you will be shocked at the clarity (for the crappy design that the headlights are). Then use another polish that you like (step is optional).
Whatever you do, do not WAX the headlights afterwards for at least 1 month. I have no facts to back this up as to why, but I wouldn't use WAX.
If you follow those steps, take your time!!, you will have kickass results! I just described it in detail but it is not hard and worth the time (for me at least)
For the inside I put soapy water in mine and sloshed it around. I then spent forever rinsing it out. This left a lot of water spots when it dried, I do not recommend it