This method takes a long time and is to be performed on lights that are in extremely poor condition that is comparable with this image:
20150920_195234 by Richard Fanders, on Flickr
Prise apart the lens from the body, use a hair dryer to soften small sections of the adhesive and prise apart with a plastic lever careful not to scratch the black paint. A heat gun is not necessary as the hair dryer was easily hot enough to soften the adhesive.
2015-09-29_09-45-31 by Richard Fanders, on Flickr
Get a sanding block and sand horizontally only (this is very important) with either 60, 120 or 180 grit sandpaper. You need to remove all the plastic coating that was cracked. 60 grit took me 10 mins 180 grit took me an hour.
Here are the results from 60 grit:
60 grit by Richard Fanders, on Flickr
Here is 180 git, much finer but really struggles to take the plastic off and had to use a lot of sand paper:
180 grit, horizontal cross hatch by Richard Fanders, on Flickr
Then 320 dry sand paper:
320 grit, horizontal by Richard Fanders, on Flickr
Then 600 wet sand paper:
600 grit horizontal by Richard Fanders, on Flickr
800 wet sand paper:
800 grit, vertical by Richard Fanders, on Flickr
2500 wet sand paper:
2500 grit by Richard Fanders, on Flickr
Very Important!
Now the very important part, notice that at every stage I alternate between horizontal and vertical sanding. This is call the "cross hatch" method. This is so you can ensure you have removed all the deeper scratches from the previous grade of sand paper. So if 320 with horizontal you can not stop sanding with 600 until you have converted all the horizontal scratches to vertical.
To summarise:
That's dry sanding with 180 then 320 grit then wet sanding with 600, 800 and finally 2500. Remember, cross hatch method and remove all the previous scratches or you will compromise your finish.
Now polish with Meguiars Headlight Restoration Kit:
2015-10-03_11-17-56 by Richard Fanders, on Flickr
