1 GET PREPPED
For the vast majority of cars, you’ll do the job with the headlights still installed. This is because most headlight units are a right old bugger to get out, requiring the removal of grilles, bumpers and all sorts.
That said, if you have a car where they pop out easily enough, say a New Beetle or a Puma, you can do the whole job on a bench if you choose to. For the rest of us, though, you’ll want to give your car a wash, and mask off an inch or two around the headlights, particularly where they meet any paintwork, before you start.
2 GET ‘EM WET
The idea here is to work your way down (or technically, up) through a few grades of abrasive, starting with wet & dry paper. The level of fading on your lights will dictate the grade you’ll want to start with, but remember that you’re not sanding off paint, the stuff you need will be relatively fine compared to what a body shop will use for crash repairs. Basically, you don’t want the really rough stuff (like anything less than 800-grit) and power sanders, because there’s a chance you’ll do irreversible damage to the surface. If in doubt, always start with a higher grit than you think you’ll need, you can always go back and do it again.
Personally, I like to work through three grades – 1200-grit, 2000-grit, and 3000grit (the last being a handy foam-backed pad). But you can use as many grades you feel are needed; it will simply take a while longer. There’s no prizes for being the fastest anyway.
The most important thing is to keep the surface wet while you’re sanding; all you need for this is a spray bottle filled with water. I also like to pop in a little washing up liquid for lubrication – possibly the only time it’s actually okay to use a household detergent on your motor.
3 SAND AWAY
Once you’ve given the lens a good soaking, you can start with the coarsest grade of paper. Don’t go mad; you don’t need much pressure for it to work, and always make sure you use a new piece for each light. A quarter of a standard sheet will be fine, and it won’t take long – you’ll actually feel it go all slippery as you work.
Most importantly, only sand in one straight direction, keeping the paper flat and following the contours of the light. The old ‘ wax on, wax off’ impression is no good to you here as it’ll only inflict swirl marks. Oh, and make sure you don’t let it dry out while you have the abrasive in contact with the lens.
Once you’ve completed the whole light, wipe it off with an old microfibre and a squirt of alcohol-based glass cleaner (or panel wipe), let it dry, and you’ll see it’ll be all scratched and hazy… er, don’t panic.
4 MORE WET SANDING
Now you can jump to the next grade – in our case the 2000-grit. Get the headlight wet again and work by sanding in the opposite direction. Wipe that off and check your handiwork; it should be a little less hazy than before, right?
Spray it down again and then get to work with the next grade (3000-grit here), sanding in the original direction. You’ll find that after you wiped that off, it’ll start looking a bit more like a clear lens. Phew, this is about the point where your heart stops racing, and you realise that this stuff actually works!
5 SHINE THEM UP
The last stage uses the same principle as the sanding and again you’ll be using various grades of abrasives. The difference here is that the abrasives will be polish and compounds, and you’ll be going in dry, so to speak.
Here I used a compound (a paint restorer) followed by a fine polish, but that’s not set in stone – you can use as many different products as you feel you need to – just make sure that you start with the coarsest and finish with the finest, and use a different applicator for each. The more polishing you do the better the finish will be.
You can also use a machine polisher if you don’t fancy the elbow grease but, to be fair, there’s not too much effort involved in doing the job by hand, and you get far more control.
With these final compounding/ polish products it’s best to use light pressure and a circular motion to cut out the extremely fine scratches you’ve previously inflicted with the last stage of wet sanding.
Apply your products, buff them off, and when you’re happy with the supershiny finish, you’re done. That was easy, wasn’t it?