Headlight Restoration - Using The 3M Kit


  1. Heckler
    Difficulty Level:
    I thought I'd write a little guide for restoring your headlights using the 3M Headlight Restoration Kit.

    Headlight fogging is quite a common problem on modern cars, it happens when the sunlight starts to breakdown the sealant on the outer layer of the plastic, or wear and tear, scratches and so forth damage it. Once this barrier fails, UV light can get directly onto the plastic and it starts to oxidise. This leads to discolouration and fogging of the lens cover. It looks unsightly and can eventually lead to an MOT failure if it gets bad enough.

    So on to the tools you will need.

    1: Cordless drill - An electric one would also suffice, but you want one with a variable speed. Ideally you want a drill in the 900-1500rpm range and most cordless ones will suffice. I have 2, a 12v and an 18v. I used the faster one for the initial sanding and stage 1 polishing, and the second for the final polish
    2: The 3M Headlight Restoration Kit - This contains everything you need to restore your headlights covers to virtually new cosmetic condition. I'd advise buying some extra automotive tape, it's a small roll included in the kit, and whilst fine for cars with smaller/compact headlights. Those on the accord are rather large. I used several layers to help protect the paintwork and used over half of the included roll.

    You can find the kit here -

    At the time of writing this, it is £15.99 with free delivery.

    3: New sealant for the plastic lens cover to protect it from UV light that will cause the issue. I'd recommend getting some of this even if you don't have the problem yet. It will help prevent it from occurring in the future.

    Sealant can be found here -

    At the time of writing this, it's £7.99 with free delivery on orders over £20 (if you buy this with the 3M kit, that's covered)

    4: Some more automotive tape... this is easy enough to find and varies in price from £3 to £7-8 per roll. It depends on the length/width of the roll you buy.

    5: A spray bottle with some clean water in it, make sure it's a bottle that sprays a mist rather than a stream/jet. I simply reused an old Mr Muscle bottle that I cleaned out thoroughly first.

    So onto the process itself.

    A quick before pic to show what years of normal use, and a lack of preventative measures will do to a headlight. When I took this photo it was very dull and getting dark. So it's not a great one. It's also worse in real life than it looks in this pic.


    Stage 1

    Clean the headlight thoroughly to remove any dirt, dry off properly.

    Apply as much tape as you want around the entire headlight, poke it into the grooves and extend it as far as you need to. Personally I think 3 layers is required up close to the light and 2 a bit further back. Covers you for any of those slips you might make if the drill torques out of your hand or bites into the plastic harder than you planned for if you applied to little or too much pressure.

    Take the 500 grit (gold) disc, stick it on the pad and insert into the drill. Start the drill and gently apply pressure and move the drill back and forth evenly over the surface of the headlight. Keep going until the whole light is evenly covered and looks frosted. Replace each disc as needed. I used 3 of the gold discs to do one headlight (there are 8 in the kit).

    What you should end up with is something that looks like this, If it looks streaky, it's because I'd wiped over part of it to check if it looked even. If it looks uneven repeat the process until it all looks good.

    Once you've done this part, wipe over with a dry lint free cloth to remove residue.

    2015-07-31 13.00.32.

    Stage 2

    Swap the disc for the 800 white one (there are 4 in the kit), and repeat the sanding process. You'll start to see the sanding marks in the cover reduce down and become less visible. Again it's important that you do this evenly and apply gentle pressure. Replace discs as they become clogged. I managed to do this process using just 2 discs.

    Wipe over once more with a dry cloth to clear residue and inspect your work. If there are rough spots still or it looks uneven... repeat the process until it all looks good.

    You should end up with something like this.

    2015-07-31 13.14.10.

    Stage 3

    Take out the green/grey small foam disc. This is polishing disc stage 1. Spray the pad itself, not the headlight until it's nice and damp. Then using the same process as before, slowly and gently apply pressure to the headlight, moving back and forth. Never let the pad run dry, keep it moist. I found that a spray every 15-20 seconds of use was more than enough.

    This process can take a lot longer than any other so far... So persevere with it, the end results will make the effort worthwhile.

    Once you are done, wipe over with a damp cloth to remove all residue and inspect... Repeat until all of the scratches are gone and you are left with what looks like a light haze to the plastic cover.

    If you still see scratches in the cover, you may need to repeat steps 1 through 2, or just step 2 before polishing again.

    It should look like this... and as you can see... the results are already pretty spectacular. All of the scratches and fogging is gone and the headlight is starting to look like it used to again.

    2015-07-31 13.46.39.

    Stage 4

    Remove the green/grey polishing disc and fit the larger and thicker dimpled orange foam disc. Open the packet of compound that comes with the kit and apply a decent sized blob about the size of a large pea in the centre. Then rub the disc over the lends a little before turning it on. At this point I switched to the lower RPM cordless drill as well. If you have a variable one, reduce it down to around 900-1000rpm.

    Very gently start polishing the cover, you'll be using less pressure than you did in the other stages. Let the pad waft over the lens.

    Important - Under no circumstances let the pad go dry, apply a new pea sized blob to the disc every now and again.

    As before with the stage 1 polishing, this will take a long time... Longer than the other 3 combined in my opinion (although I wasn't timing myself). just keep going, adding compound and polishing away until you get a headlight that looks like it was just installed from new.

    Hopefully... if everything you have done went as planned. You will end up with a headlight that looks a lot like this.

    2015-07-31 13.54.58.

    Stage 5 - Almost Finished

    Clean the headlight thoroughly with some warm soapy water and dry properly with a clean lint free cloth. It's important that you remove any and all traces of dirt and residue.

    Take the sealant and open it up... Careful as the first time you press the top it can squirt out a little... Cover with a lint free dry cloth that you will use on the headlight to catch anything. I didn't, and I had to wipe it off my hand and t-shirt. :Smile:

    Apply a decent sized blob onto the cloth, I reckon the bottle should do at least 5 or 6 applications (50ml bottle), gently rub it all over the light until every part is covered in a haze. Leave to dry for about 5 mins and then clean off. I gave it 2 applications to be certain, and I shall give it another in a few months time. This sealant says it will stop 98% of UV light, which is what causes the problem in the first place.

    Once you are finished and satisfied with the result. Remove the tape and clean up all the dusty residue.

    What you should end up with is something that looks like this.

    2015-07-31 14.02.58.

    For a grand total of £27 for all of the things needed, and about 90-120mins of my time, plus the leccy needed to charge up the cordless drills... It's certainly a project everyone can do.

    The results speak for themselves, it looks almost as good as new... and if you think you can see some marks, I gave it a final polish with a clean dry cloth to remove a few small traces of residue from the sealant I'd missed before I took the pic... and I forgot to take another one after as my phone ended up in the bottom of the box as I was clearing up.

    It has not only saved the headlight from being replaced, which in turn has saved me at least £80 for a second hand scratched up one, or a £100 for an after market one... But it's saved me from a potential MOT failure in Dec and the cost of having to replace it anyway. When you factor in both lights need doing (I'll do the other one next week as I'm busy from now until Tues)... £27 instead of a potential £160-200 is a huge money saver too. Less than £14 per headlight.

    I'd give it a difficulty rating of 2 out of 5 (1 being easy and 5 being hard).
    - - - Updated - - -
    Hmmm... the links to the kit and sealant are there in the post when I checked it, and if I edit... they're there. But they're not showing up in the actual post. I assume that this may be some kind of permission thing. If a mod can make them appear, and if you want to add this to the guides section, please do.

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  1. DrSam
    Just what i needed
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    one of the many things i have yet to do to my car!
  3. nauest
    Sweet! Great to see it work so well
  4. mustnap
    nice DIY instruction there. will try to do this myself
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