Dealing with foggy headlights? I’ve been there. After trying a few DIY techniques that didn’t work (like toothpaste and rubbing compound), today I wanted to share what actually worked well: wet sanding.
If you have a set of hazy headlights, the wet sanding process isn’t as difficult as you may think.
In this blog post, I’ll break down a step-by-step process that worked for me and how to protect your headlight lenses in the final step. Keep in mind that this is a DIY solution, and individual results may vary.
The wet sanding process can be pretty messy and time-consuming. Budget somewhere around 30 to 45 minutes per headlight to achieve the results you want; this time depends on how cloudy your headlights are.
What you’ll need
- Painters tape or masking tape
- Garbage bags or plastic
- 400-2500 grit sandpaper (600, 1000 and 2500 is common) but numerous grits from 400-2500 depending on the cloudiness
- Spray bottle with water
- Car soap
- Isopropyl (rubbing) alcohol
- Polishing compound
- Liquid car polish
- Multiple microfiber towels
- Foam buffing pads
- Drill with polisher attachment (or polisher)
- Face mask and glasses
- Rubber gloves
Step 1: Mask off the headlights and cover the paint
Before you get started, it’s a good idea to tape off your headlights with painter’s tape since you will be using sandpaper. This will make it quicker to work since you won’t have to worry about making contact with the paint. I was careful around the edges, but will definitely do this in the future.
Using your garbage bag or piece of plastic, cut a hole the same size as the headlight and mask it off using painter’s tape. This is totally up to you, but unless you plan on washing your vehicle after the headlight restoration process, you will likely be dealing with dust (or dried dust) from wet sanding.
Step 2: Start with dry sanding
I recommend you wear gloves and possibly a face mask and glasses for this step, since dust tends to fly around a lot when dry sanding. Once you add water, things can get messy.
Start with 600 to 800 grit sandpaper and apply horizontal strokes left to right. I picked up a pack of rectangular sandpaper sheets in different grits on Amazon for a few bucks.
They can find handheld palm sanders made of foam that are a bit more comfortable; these come with circular sanding sheets you can swap on and off.
Technically you can use an orbital sander (or DA polisher) with sandpaper disks, but I don’t recommend them for beginners; it’s far too easy to apply too much heat to plastic.
For beginners, sandpaper (or a sample handheld sanding block) usually works pretty well unless you have an extreme case where a power tool will save you some time.
What is this white or yellow haze anyway?
The white or yellow haze is typically a combination of degraded plastic particles and a UV coating. Manufacturers generally apply a layer of clear UV coating to the headlight surface. This coating helps to protect the plastic from fading or turning yellow over time. Over time, UV rays from the sun will degrade the EV layer
You’re essentially removing all the surface-level oxidation (which can be a lot of hard work!) by dry sanding to expose fresh, clear plastic underneath. Dry sanding with large grit sandpaper works best to remove large dust particles, wet sanding is ideal for polishing.
Step 3: Wet sanding with 800-2500 grit sandpaper
Water acts as a natural lubricant when polishing out scratches caused during the dry sanding process; water also helps keep debris from clogging the finer-grade sandpaper.
After dry sanding with heavy grit sandpaper, take your water bottle (or a bucket of soapy water if you prefer) to cleanse the surface. When clean, switch to a lower grit sandpaper and add water to begin the wet sanding process. If you started with 600, wet sand with 800. If you started with 800, wet sand with 1,000 grit..and so on.
In between these phases, spray down the surface with car soap and water to remove any milky liquid.
Use a crosshatching technique if sanding by hand
When wet sanding, I recommend a crosshatching technique to help remove scratches as you work. Make diagonal passes before alternating directions with the heaviest grade sandpaper to start. The headlight lens should gain more clarity as you step down to fine-grade sandpaper. Using circular motions can be effective at gaining clarity, but is difficult without a machine polisher.
Step 4: Apply a compound
After you rinse and dry the surface after your last phase of wet sanding, the surface may still be somewhat hazy, but smooth. Now is a good time to use a dual-action polisher to apply either a paste or liquid compound. A wool pad will provide more cut than a foam pad, just be careful not to generate too much heat.
Check out our post on polishers 101 if you’ve never used one. We cover how to load a polishing pad and which one we recommend for beginners.
Apply a decent amount of product to a clean pad, and evenly apply it to the headlight lens.
I just used a polisher attachment for my drill in this example, for best results you’ll want to use something a bit more powerful.
You don’t technically have to use a compound and can skip polishing if you prefer; since a compound contains grittier particles, it can help remove any of the leftover oxidation you may have missed with sandpaper.
Step 5: Apply a liquid polish
Always apply polish after you compound. Polish is less abrasive than compound so it will smooth out any micro-scratches produced by the compound itself. Since this is a multi-phase process, be sure to have plenty of damp microfiber towels on hand.
If you’re a little confused about the difference between polishes, compounds, or waxes (and what they do), check out our post: Compound vs Clay, Polish & Glaze! 7 Products to Understand.
Step 6: Finish with isopropyl alcohol
After you have removed the polish and buffed the surface, everything should look pretty clear. As a best practice, apply isopropyl alcohol (or an IPA wipedown solution) with a microfiber towel to remove excess product. Isopropyl alcohol—or rubbing alcohol—can remove almost anything, like glue or polish. Just be careful not to make contact with rubbing alcohol on surrounding areas like trim work as it can discolor some plastics
Step 7: Evaluate & repeat if necessary
Before you seal in your work with a coating, take a minute to evaluate your work. You may need to repeat a few steps in the process if you still have cloudy headlights.
Sometimes the headlight lens may be damaged from the inside due to moisture or cracking, in which case there isn’t much you can do outside of replacing the headlight lens itself.
Step 8: Apply a protective coating
If you are satisfied with the clarity of your headlights, it’s a good idea to apply a protective coating. These coatings help protect the plastic in your headlights so the lenses maintain clarity for a lot longer.
Meguiars makes a headlight coating specifically for this purpose that I use, but you can find a variety of UV coatings from manufacturers like Sylvania or Spraymax.
Apply this coating as evenly as possible in light coats, because it can bead up and dry on contact if not careful. It’s always best to apply several light coats than a heavy one, especially since you will already have everything taped off.
Inspect and repeat the process as needed
As you can tell in the picture below, I did see a drastic improvement in clarity after wet sanding as opposed to compounding and other DIY techniques I’ve tried.
You may need to repeat this process over time, as plastic will fade out again. In circumstances where the plastic is very old or brittle, you may want to install a set of aftermarket or OEM headlight lenses to save yourself the trouble.
Wet sanding vs. headlight restoration kits
While you can definitely use a headlight restoration kit, I’ve always found wet sanding more effective for severely damaged headlight lenses.
Most of the kits on the market include a few sanding discs, a cleaning solution, and sometimes a UV protectant. These kits work well in many cases, I just prefer more sandpaper in more grades for severe restoration jobs. Sandpaper packs with a mix of all grades are pretty cheap, and you can assemble everything in most headlight restoration kits for a fraction of the price.
Overall, removing scratches and getting total clarity is a bit more difficult than you might think, but well worth it to make an old car look newer.
I hope this post has been helpful if you are considering tackling wet sanding. Let me know in the comments any additional tips to be aware of!