Cleaning headlights - Baking them in the oven


Well-Known Member
Mar 28, 2010
I read somewhere that you can get the lenses off your headlights by putting the headlight unit in the oven just long enough to soften the glue so the lense can be prized off - and I can honestly attest that it works. Just a few months ago I used exactly this method to remove both my headlight lenses and clean the refectors after the lights had filled up with part of Salisbury plain.

Unfortunately Lincomb resulted in both lights needing to be cleaned again. So, seeing as this job is a PITA I decided this time I would do a "proper" job. The plan was to get the lenses off and remove all the old glue replacing it with good quality silicone. The advantages being that it would improve water-proofing and make it much easier to remove the lenses in the future should I ever need to again (i.e., without having to bake them in the oven).

Here's how it went.........

First headlight before baking:

After spending literally hours painstakingly removing the old glue and successfully cleaning:

Then things went a bit pearshaped. With the first headlight I had experimented with both heating and freezing the light to see what made removing the glue easiest. None of it helped. Heating made it stickier so that it stuck like s**t to anything it touched. Freezing set it like concrete. In the end it had been best to work at room temperature scraping and removing the glue piece by piece.

I decided what was needed was more heat. I had noticed that in cleaning the glue off the lense, when heated up just a little bit more the glue became runny and could be largely wiped off. So, back into the oven the unit went for a mere 5 minutes - bearing in mind I had baked them for 10 to get the lenses off.

Unfortunately I failed to account for the fact the oven was now preheated :oops: :oops: :oops:


In total I spent just under 6 hours to achieve one clean headlight and a requirement to buy another. Took me about 30 minutes to get the headlights out of the truck, another 30 minutes to bake both units and get the lenses off, seriously about 3 hours to get all the old glue off the first light :evil: , and nearly 2 hours to remove the second light from the oven shelf it had morphed with and remove all the molten plastic from the oven and oven shelf. 5 bl**dy minutes :evil: :evil:

It would have been cheaper and easier to have bought new headlights!

180 degrees, fan assisted for those interested.



Well-Known Member
Mar 28, 2010
The rubber boots on the back of the lights are split which is where I think the muck got in. Though I'm also convinced the seal around the lenses was never properly watertight. The rubber boots are getting replaced!

At Lincomb it was reversing out of the mud hole that filled the lights. I think I may have reversed with a bit too much welly causing a wave to gather under the bonnet :roll:
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Jon Wildsmith

Super Moderator
I am in england
Feb 24, 2010
Stourbridge, West Midlands, England
The OEM motorized lights might have more open backs as well than the cheap after market ones. I don't think my originals lasted all that well but then the Milner ones I replaced them with lasted for ages before they were too dirty to use.


Well-Known Member
I am in uk
Aug 10, 2010
Witham, Essex, United Kingdom
Mmmm.......well for me that just reinforces what I said in the original thread on this subject :)

Life is just to short :p


sae70 said:
I don't envy you this task :roll: The last time I did this was to replace a cracked lens & it took me ages & left me all :twisted: :twisted: :twisted: Once the lens was off I used a hot air gun/paint striper type of thing to soften the mastic then just slowly worked around the groove with a flat blade screwdriver & a Stanley knife gradually removing all of the old glue over a period of time like the rest of my life :twisted: :p

It is doable but what a bitch of a job :thumbdown:

If you do manage to do it don't then use to much mastic/glue when putting it back together as it makes a proper mess if you do :( Remember just enough if anything go just under put the lens on then have a look to see how much more you need remove the lens top up with mastic/glue then drop the lens back on :lol:

Good luck :thumbup: I'll say a little :pray: for you :D

I shant ever be doing it again though :) Lifes to short :p


New Member
Dec 26, 2010
Read somewhere that a turn in the dishwasher can turn headlights sparkling again. Anybody tried it?


Well-Known Member
Apr 6, 2010
South Normanton. Derbyshire
Is it not possible to soak them, then use a steamer to clean the crap out from behind, then seal it all once dried? I've known of someone drying them out using silver foil over the front to reflect the heat from the main beam !

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