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How to clean and restore your headlights

How to clean and restore your headlights

Your headlights are an essential part of your car's lighting system. As well as illuminating the road ahead for you to see in poor conditions, they're also imperative for signalling to other road users where you are in relation to them on dark roads.

Although your headlights are protected by sealed housing, they aren’t completely immune to occasional build ups of dirt, debris, fogging, and other issues that can reduce their effectiveness. You run the risk of getting into trouble with police if your headlights do not meet the legal brightness requirements — they must be bright enough to see 100 metres ahead without startling any oncoming cars. So, you'll need to maintain your headlights often to ensure are working properly.

But how do you know when it's time to clean your headlights, and how do you do it? In this guide you'll find everything you know about restoring your headlights. We'll cover:

Why should you clean your headlights?

Why should you clean your headlights?

Your headlights are an important feature for your car, so it's important you keep them in good working order — and this includes cleaning them often.

As well as ensuring you, other road users, and pedestrians are kept safe, cleaning your headlights means greater visibility if you're driving in poorer conditions. It can also help you maintain their functionality and performance, as well as the vehicle's overall value.  

When to clean your headlights

When to clean your headlights

Like any headlight issue, as they're not easily visible by the driver, it can be difficult to know when your headlights will need cleaning. While they might look a little mucky to the eye, the problem typically starts within the headlight housing and builds up until it's visible from the outside, too.

For example, one specific problem that car owners often see is the headlights becoming foggy, and this is due to chemical reactions between the exposed plastic and the sun's UV rays. So, it's important to stop this in its tracks, to prevent it from getting worse and reducing the brightness of your headlights.

Other problems may arise if the sealant that holds your headlight housing in place has worn away or become loose, as this can mean dirt, dust, and debris from the roads are able to seep through. In turn, this can cloud up your headlights and even cause damage to the housing, bulb, and electronics, which may be costly to fix.

Generally, it's best to tend to your headlights every time you clean and detail your car, which might be as often as every two weeks. If you think your headlights stay relatively clean for longer than this, you can go a week or two longer, but you should never leave it months as it can make it harder to spot other more dangerous issues. This could include engine oil build-ups causing exhaust smoke, car radiator leaks, and many more external and internal issues that will need sorting sooner rather than later.

While frequent cleaning and maintenance can keep your headlights working for longer, if you notice that your headlamps are flickering, seem dimmer, or one is out, it's a sign that you may need to change your headlights.

How to clean your headlights

How to clean your headlights

Most headlights are made from tough polycarbonate plastic that is ideal for when you're travelling across uneven and rough roads, but it doesn't always deal well with prolonged exposure to the sun. Despite initially having a protective UV film, this eventually wears down and can allow the plastic to oxidise, which is the leading cause of hazy or yellowing headlights.

To clean plastic headlights that have gone foggy, you'll need the following:

Once you've gathered the above, we've found the best way to clean your headlights is to follow the below method:

  1. Clean your headlights thoroughly with some warm, soapy water and a car sponge — you might also want to wash the surrounding areas so that the painter's tape will stick onto your car well in a minute.
  2. Tape over the bodywork surrounding your headlight cover using the painter's tape. This is so any slip of the hand won't mean you're then having to remove bodywork scratches.
  3. Wet your headlight and choose the most abrasive sandpaper option you have available to you (tip: the lower the number, the more abrasive it is). You should also then wet the sandpaper. You'll need to make sure the headlight is wet at all times to avoid badly scratching the lens.
  4. Sand the headlight lens in straight horizontal strokes, taking care to only work in one direction at first and clean the lens when you start to see a good proportion of the fogging being removed.
  5. Repeat the above process using the different types of sandpapers you have (gradually getting less and less abrasive). For these next ones, you'll want to sand in the opposite direction to the first time, so we'd recommend working diagonal for the next one, and your last sanding should be in a different direction to the diagonal you just did.
  6. Wipe off any debris and clean your headlights with the soapy water again. Dry them with a microfibre towel.
  7. Add polish to another clean microfibre towel and rub the polish onto your headlights in a circular motion.
  8. When the lenses are clean, you can then add the wax. You can find further information on applying wax to headlights in our car detailing guide.
  9. Wet a paper towel and apply your headlight UV sealant in broad strokes. Be sure to check the sealant instructions as some will just require one layer, but others may work best with multiple coats.
  10. Allow the sealant to cure by parking your car in a dry space. Once it’s dried, finish the job by testing out your restored headlights!

Should you not see the results you wanted, or your headlights are heavily oxidised, it might be worth either repeating the process or ordering a replacement headlight lens.

Keeping your headlights in prime condition is essential for safety and visibility on the roads, so it's always best to avoid letting them get too dirty. However, if you've not spotted how mucky or oxidised they've already got, this guide should help you to restore and clean foggy headlights. Here at GSF Car Parts, we have a range of replacement car parts for you to browse, including bulbs, batteries, and body panels. We even have a great selection of essential cleaning products and tools to help you with any DIY car maintenance. Please note, GSF do not accept any responsibility for accidental damage caused when following this advice and advise visiting a professional if you don't feel completely confident to carry out this restoration.

If you're planning some more repairs on your vehicle, make sure you check out our other handy guides that can assist you. We have advice on everything from jump starting your car, to checking and changing your brake pads, and even a troubleshooting guide for car starting problems.