Foggy headlights don’t just take away from the aesthetic appeal of your ride — they’re also a safety hazard. By reducing light output at night, yellowing headlights impair your seeing ability, putting you and everyone else in your car in danger. 

Thankfully, foggy headlights are pretty easy to fix. What’s more, you don’t have to spend a hefty amount at the mechanic since headlight restoration is something you can do yourself. 

Here’s our comprehensive guide on how to restore headlights permanently, plus a few quick temporary fixes to try if you're in a rush.

What Causes Foggy Headlights?

When you first buy a car, all its parts, including the headlights, are usually pleasantly shiny. A few months down the line, the once shiny headlights are replaced by foggy headlights due to:

• Oxidation: Headlights are often made of polycarbonate plastic. Over time, exposure to UV radiation from sunlight causes chemical reactions in the plastic. This breaks down the bonds in the plastic, which leads to the plastic to oxidizing and becoming cloudy or yellowed
• Time and Environmental Factors: Although polycarbonate plastic headlights are typically covered using a coating film, exposure to harsh weather conditions, road debris, dirt, bugs, and harsh chemicals over a long time makes the coat peel off
• Water vapor: A damaged headlight seal can allow moisture to enter the lightbox. Condensation trapped in your car’s lightbox is also a common culprit behind dulling headlights
• Dirt and chemicals: If you’re always on the road, your car may develop a thin chemical and dirt layer, causing yellow headlights

Before Starting Restoration - Assess the Issue

The first thing you’re going to need to do is figure out the cause of the headlight fog and where it is coming from.

The quickest fix, which you likely tried, but is worth mentioning, is to clean the outside of the headlights. Sometimes the haze is just caused by a dirty film that can be removed with a good scrubbing.

Then you’ll have to figure out:

1. Is the haze inside or outside?

• Location of the haze: If the haze appears to be on the surface of the lens and you can feel it when you touch the headlight, it's probably an external problem caused by oxidation or environmental damage.
• Color of the haze: Usually, if the headlights have a yellowish or browish tint to it, the issue is exterior. It can also happen on the inside, but that is much less common since the outside is exposed to direct and longer exposure to sunlight.
• Uniformity of the haze: Internal fogging is usually caused from condensation and will appear as a more uniform haze across the entire lens, while external haze might be more localized or appear in streaks or spots.
• Visibility of dirt or debris: If you see dirt, debris, or water droplets inside the headlight, it's an internal problem.
• Response to cleaning: If you try cleaning the outside of the headlight and the haze doesn’t go away, it could be internal.
• Presence of scratches or damage: Scratches, cracks, or scuffs on the lens surface indicate external damage.

Determining where the haze is coming from will save you a lot of time from accidentally working on the wrong part of the headlights. Most of the time, the issue will be exterior. Interior problems usually occur due to an issue with the seal.

If you determine your headlight problem is due to interior fog, you can fix it by removing the headlight assembly, cleaning the inside with a microfiber cloth, drying it fully, and resealing any damaged seals. If you're not comfortable with removing and disassembling the headlight assembly, a mechanic or auto detailer can help.

For haze caused by external oxidation or headlight damage, the rest of this article will help you restore your headlights.

2. How severe is the haze?

For exterior haze:

Preventative Measures: To prolong the life of restored headlights, you should add a sealant and take other preventative measures, mentioned near the end of this article.

Below we go more into detail about how to restore your headlights with each of the methods mentioned above.

Are there any other signs of damage?

• Scratches or cracks: These can worsen haze and scatter light, reducing visibility. Deep scratches and cracks might require professional repair or replacement.
• Water damage: Water can damage internal components and worsen haze. It might indicate a seal issue that needs to be replaced.

3. What type of headlight do you have?

Different headlight types (halogen, HID, or LED) might have slightly different restoration requirements.

• Halogen Headlights are the most common type of headlight and generally the easiest to restore. The techniques mentioned in this blog post are usually the most effective ways to clear foggy headlights.
• HID (High-Intensity Discharge) Headlights have a more complex structure and use a gas-filled bulb. The basic principles of sanding and polishing apply, but extra caution is needed to avoid damaging the sensitive components. You may want to use a specialized HID headlight restoration kit or consult a professional for restoration.
• LED (Light-Emitting Diode) Headlights are generally more durable and less prone to haze than halogen or HID headlights. If restoration is needed, it usually involves a gentler approach with finer grits of sandpaper and specialized polishing compounds.

How to Restore Auto Headlights - External Haze

For moderate to severe haze, a combination of dry and wet sanding is the best, most efficient way to restore auto headlights permanently. Sanding headlights strips away the foggy layer, revealing the once shiny light lenses you loved.

Step 1 - Gather your Supplies

Here’s what you’ll need:

• Warm, soapy water (with carwash soap specifically)
• Plain water
• Soft, dry cloth
• Masking/painter’s tape
• Water spray bottle
• Wet Sanding Abrasives* -
  • For hand sanding: wet sandpaper sheets
  • For power sanding: 2” or 3” sanding discs**
• Plastic Polishing Compound
• Flannel polishing cloth
• UV resistant sealant

*For the abrasives products you’ll need several grits - 600, 1,000, and 2,000 grit. If there are deep scratches or you have severe haze, you may need to start with 400 grit. 3,000 grit is recommended by some for the last step, but we think that is usually overkill. A polishing compound is usually going to get better results and save you from having to buy more abrasives.

**For power sanding, we recommend using a cushioned foam backing pad since you’ll be sanding on a curved surface and these provide extra flexibility.

Step 2 - Clean Your Headlights

Sanding headlights without proper cleaning grinds contaminants deep into their surface, resulting in a rough, uneven surface with poor adhesion.

Fill a bucket with warm water and car wash soap. Avoid household cleaners or dish soaps, as they may contain harsh chemicals that can damage the plastic lens. Wash the headlight lenses, removing all dirt, grime, bugs, and other contaminants. Rinse the lenses with plain water until all soap residue is gone. Then, dry the headlights completely with a soft, dry cloth.

You may want to wash the surrounding areas too to help with the next step.

Step 3 - Tape Off the Area

You don’t want to accidentally sand off your car’s paint which would just turn into another new and expensive problem on your list.

Before you start sanding away, apply masking or painter's tape around the headlight area. Two strips of tape are usually enough. If you’re still worried about messing up your paing job after adding tape, you can always remove your headlights, but this will be a lot of work.

Step 4 - Sanding Headlights

Once you clean foggy headlights and tape away the area, it’s time for the real work to begin. You will need elbow grease and different grits of sandpaper to get the job done. Note, the higher the grit, the finer the sandpaper. Start with the coarsest option and gradually work your way to the finest.

That said, here are the sanding steps for this DIY headlight restoration project:

• Initial Sanding (if necessary): If your headlights have deep scratches or are heavily oxidized and cloudy you may need to start with 400-grit sandpaper. Dry sand the headlight in a consistent pattern (e.g., horizontal) until the surface is evenly hazy.
• Wet sand with 600 grit sandpaper: Using your water spray bottle, apply water (serves as a lubricant) on the surface of your headlights. Sand down your headlights using the 600 grit sandpaper, sanding in straight lines (in the opposite direction of the last step) until the whole surface is covered, and ensure you maintain a consistent pattern until you’re satisfied the foggy layer is gone.
• Wet sand with 1,000 grit sandpaper: Spray down the surface like you did in the last step and lightly wet sand using the 1,000 grit wet or wet-dry sandpaper. As advised, follow consistent sanding motions running in the opposite direction of the last step. Also, keep on lubricating the surface using water.
• Wet sand with 2,000 grit sandpaper: At this point, your headlights should be clearer, and this last round of sanding is to get that extra oomph and smoothen out the headlight lens surface. As we did in the previous step, lubricate the surface using water and lightly use a 2,000 grit wet-dry sandpaper to smooth out the surface using consistent motions, sanding in the opposite direction of the 1,000 grit sandpaper pass.

Important Notes for Sanding Headlights:

• Grit Progression: Use progressively finer grits of sandpaper, starting with a coarser grit and gradually moving to finer grits.
• Wet Sanding: Always wet sand, except for the initial step if you’re using 400-grit sandpaper. Wet sanding helps prevent scratches and keeps the sandpaper from clogging.
• Sanding Direction: Change the sanding direction with each grit progression (e.g., horizontal, vertical, circular) to ensure even removal of oxidation and prevent directional scratches.
• Consistent Pressure: Apply even pressure and avoid excessive force, which can damage the lens.
• Lubrication: Keep the surface wet by frequently spraying it with water.

Step 5 - Clean and Polish

With the cloudy layer gone, your headlights will now be clearer and looking almost new again. If you want to get that showroom sparkle back, you'll need to clean and polish them. Wipe the surface using soap and water to remove sanding debris, and then rub in your polishing compound with a flannel polishing cloth using consistent motions for an extra shine.

Alternatively, if you want to use your power tools, you can also buff and polish your headlights using a cotton buffing wheel on an angle grinder or a felt roloc polishing pads with a drill or die grinder. Instead of a polishing compound, you would use a blue rouge buffing compound bar with these kinds of buffing wheels. Just make sure you run it on a low setting that won't heat the plastic surface too much which could cause damage to the headlamp.

Step 6 - Apply UV Sealant

Although sanding your headlights is a somewhat easy and efficient way to restore headlights, it's not something you want to have to do all the time. If you want to remove the cloudy look for a long time, you'll need to finish off this project with a UV sealant.

Applying a UV sealant keeps headlights from oxidizing again. You’ll want to use at least three coats to preserve that amazing headlight shine you achieved through sanding. To keep your headlights protected from oxidizing again, you can reapply the sealant every few months or use a headlight protection film that lasts for several years.

Sanding is the best, most efficient way to restore auto headlights permanently. Sanding headlights strips away the foggy layer, revealing the once shiny light lenses you loved. Here’s what you’ll need:

• Warm, soapy water
• Plain water
• Soft, dry cloth
• Masking/painter’s tape
• Sandpaper sheets - 600, 1,000, and 2,000 grit
• Plastic Polishing Compound
• Flannel polishing cloth
• UV resistant sealant

Quick (Temporary) Fixes to Restore Headlights

Sanding is efficient, but it calls for elbow grease and is time-intensive. Below are some easy, temporary fixes you can use to clean foggy headlights when time is an issue. These methods mostly just clean the surface dirt and light oxidation, but won't fully restore your headlights. If you’re happy with your results from any of these techniques, you may be able to finish off your headlights with 2,000 grit sandpaper and polish, seal them up, and get a more permanent fix.

Toothpaste

Besides brushing your teeth, toothpaste has 101 other uses, including restoring your headlights. It contains slightly abrasive ingredients that break down oxidative contaminants on the lens surface.

Mix toothpaste  with baking soda and evenly rub it onto the headlight’s surface. Let it dry, and then wipe off using a soft wet cloth. Your headlights will be clearer than before, and you’ll be set for the next few night errands.

Use Baking Soda and Distilled Vinegar

Similar to toothpaste, baking soda and vinegar are incredibly versatile products. While cleaning auto headlights, baking soda breaks down the contaminants, while vinegar efficiently removes the grime.

Mix one part baking soda with one part vinegar to create a fizzy paste. Rub the paste on your headlights, let it sit for a few minutes, and then use a soft cloth to wipe it away. You will have shinier headlights in no time.

Use Coca Cola

Yeah, you read it right —  your favorite drink can also restore auto headlights. It contains phosphoric acid, which is quite efficient in removing rust and stains. 

Transfer a can of diet coke (it’s easier to clean since it has no sugar residues) into a spray bottle and spray a reasonable amount on your headlights. Let it sit for a minute, and then dry it using a microfiber cloth. If your headlights are heavily oxidized, you may have to repeat the process several times.

Restore Auto Headlights with Dish Soap

For this method, first, wipe off your headlights to remove dust and other debris. Apply some hot water and dish soap, and leave it to sit for a few minutes. Wipe in circular, consistent motions, and rinse. Repeat the steps as needed.

Dryer Sheets

It may seem more unusual than the Coca Cola option, but dryer sheets can be surprisingly effective for cleaning lightly hazy headlights. They contain fabric softeners and anti-static agents that help to break down dirt and grime, provide a mild abrasive action, and reduce static clung to prevent dust and dirt from clinging to your headlights for a bit.

To use dryer sheets for headlight cleaning, dampen a sheet with water and rub it gently on the headlight in circular motions . Then, rinse the headlight with water and dry it with a clean cloth.

Preventing Headlights from Oxidizing

While foggy headlights aren’t completely unavoidable, check steps you can take to keep headlights from oxidizing fast:

• Park smartly: the main reason why headlights yellow out is UV radiation — parking your car under a shade whenever you can is the easiest way to slow down headlight oxidation.
• Wash your car: As noted, car headlights sometimes get cloudy due to dirt and chemical layer. Washing your vehicle regularly using the right cleaners helps prevent fogging.
• Sand your car headlights periodically: You don’t have to wait until your headlights are completely yellowed out to sand them out. Sanding headlights once every few months if you notice any bit of haze or scratches showing up. This will keep them looking as shiny as they were when you first bought your car.
• Reapply UV sealant regularly: Every few months, you can add more sealant to replace any that has broken down from the elements, adding a fresh layer of protection.

Restoring Headlights Permanently

Headlight restoration is a project you can handle yourself on a slow Sunday afternoon by following the tips above. However, keep in mind some of the DIY headlight restoration techniques are only effective for a short while. Sanding is the best option to restore headlights permanently.