MX5 NC Headlights dirty/misty?

Hello guys!

It was brought to my attention by a friend that my headlights might need to be refurbished or replaced in some capacity.

What do you guys think? I will admit they’re definitely dirty on the inside and honestly the more I look the more dirt I find; its also a little bit green around the edges…

My question is: How can I fix this? What tips do you guys have? Should I just get them replaced?

P.s: I have attached all the screenshots in an Imgur if they don’t embed properly here!


On my Polo rather than my MX-5 I’d be interested to hear answers to this - I have one side that is noticeably duller and mistier than the other. I researched and bought some special paste for this job a while back and it’s utterly useless.

Edit - The stuff I bought was K2 PRO LAMP DOCTOR. Wore my arm out using it and there was no difference.

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Just use a decent polish on them. Autoglym resin polish did the job on mine which were looking similar to yours.

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T-Cut is good for reviving plastic headlights, you have to put some effort in though but the results are worth it.


do you apply it to the outside? Or inside? And thanks :smiley:

Autoglym paint restorer on the outside does a fine job

I have a weird assortment of Autoglym products reckon any of these will do? haha

Autoglym do a headlight restorer kit which works well. I’ve used it on my NC and on my daughter’s Polo.
Comes with an assortment of sanding discs and a paste.
About £25.00 I think

I used BRASSO on my MK2 from the £ shop.

When they are really badly degraded you may need to use sanding discs, abrasive paste and then polish. Best to just try with polish first. If that doesn’t work go up a stage to Autoglym paint restorer or T-Cut.

Some people say to use toothpaste. Basically you need to return the degraded surface of the plastic back to smooth and shiny.

Unfortunately, what you need is a mild abrasive polish and none of those products fits the bill.

Turtle wax headlight restorer kit.

Cheap and does the job.

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Please mask the paint before anything is tried.
Getting rid of the seal-mould is the tricky one.
No idea about that, or the dirt on the inside…bar removing it all ( Oh Gawd no!) and dealing with them in the kitchen sink.
I shudder at the cost of replacing TBH, and the cost/benefit ratio.
Around £500.00 new, £200 odd used decent.
Anyway, no need for marginal fogging on the outside to need expensive bottles.
Like a lot of replies for alternatives I’ve used CIF cream and a soft cloth or sponge for as long as I can recall, finished off with a car wax. Got the idea form SWMBO cleaning classroom whiteboards. Always comes back eventually.
Oddly, our Mk2.5 lights are fine on the inside even now.

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Unfortunately none of the above are course enough and will take you forever.
I used Farecla G3 Compound Paste which is a product used by the professional body shops. You can buy it in a 400 gram tube.


See my post here regarding this very subject… I’d highly recommend the Autoglym kit!

As stated and recommended above.
Mask off and prep well first.
From my experience you won’t go far wrong with a bottle of Cif OR Brasso.
Both very mild abrasives/additives.
Brasso works very well on the majority of plastics including watch faces.
The only draw back with any of the products is you will need plenty of elbow grease!!
(I did buy a purpose type of product once and ended up using Brasso in the end anyway).
All a matter for your good self. :+1:

Ruddy polycarbonate lamps are a pain eh?
I’ve a personal “theory” that the internal fogging is caused by intense bulb heat reacting with the plastic rather than contamination.

I’ve noticed some headlight bulbs (but by no means all) claim to have a “UV cut filter for use with plastic lenses.” This and compliance with ECE R-37 is worth looking for.

Also many “White” LED lamps are actually UV emitters exciting a phosphor to produce the light, so again a source of problems for plastics if their UV leaks past/through/around the tiny thin phosphor layer.

See the ECE regulation R-37 summarised in this 5MB R037r7e.pdf doc

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I have used, on my Mk2.5 SVT and a Nissan Micra, 800 grit wet&dry paper followed by the finest wet&dry you can get 2500 in my case then sprayed with clear lacquer the finish is headlights that look like new units. There are many YouTube videos on headlight refurbishment just ignore the ones saying things like using toothpaste etc…

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Imho, it all depends on how badly oxidised they are.
If they are pale brown and almost opaque, then aggressive measures are called for.
If there is just a faint bloom then mild abrasives will work fine.