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How to Clean Inside of Headlight Lens

Have you ever taken a good look at your headlights? I mean an in-depth look. If you haven’t, run out and look right now. I will wait. Chances are the inside of your headlights are hazy, dirty, or even infested with bugs or moisture. Do you know how to clean the inside of a headlight lens? If not, you are in the right place. Even if you have tried before, I have a tip or two that might help make your lenses even better.

The Why: How to Clean Inside of a Headlight Lens

What is wrong with a little haze or moisture inside the headlight. Your car lives in the outdoors, being beaten by the elements, so it is bound to show some wear and tear, right? While that statement is true, your headlights need to be maintained just like the rest of your car. I will give you three reasons why.

1. Cosmetic Perfection

Maintaining your car’s head-turning beauty includes the headlights. Dirty and grungy lights are a lot like the creepy house in the neighborhood with yellowed and broken windows, you admire the architecture, but those windows make you feel like something evil is going on inside. Less than pristine headlights can make even the most magnificent paint job look dull.

So, to avoid looking like a rolling haunted house, make sure you shine and protect those headlights inside and out.

2. A Clear View

Reason two is all about being able to see clearly. Remember that night when you were driving through the forest? The brisk night air is playing amongst the trees, moonlight dancing through the branches and casting mysterious shadows across the road. Suddenly your lights catch a deer darting out of those shadows. Your headlights saved you and the deer.

Dingy and dirty headlights mean that next time you may not see the deer or the little kid on the bike. Keeping clean inside and out lets your headlights do the best possible job they can. Whether you are taking an evening drive or catching your teenager in the act, your headlights mean safety for everybody.

3. Functionality

If you have bugs, moisture, or dirt inside your headlight lens, it may indicate a problem with your lens seals or a crack in the lens itself. By performing routine maintenance and internal cleaning, you can identify any structural issues that may lead to mechanical and electrical difficulties in the future.

The Process: How to Clean Inside of Headlight Lenses

Cleaning the cover of your headlights requires just a bit of mechanical aptitude ( >>> Find out how to clean headlights with household products). I will describe two methods of cleaning the inside of your headlight lenses, and each technique requires you to remove the headlight and lens from your car.

Step 1: Remove the Lenses

The process to remove your lenses isn’t tricky and usually only requires a screwdriver, or in some cases a socket set. Your owner’s manual or a vehicle repair guide will show you the correct method and necessary tools needed to remove the headlight lens.

After removing the mounting screws or bolts, gently pop the lens out of the vehicle frame. Don’t force the lens out; you may end up damaging the gasket seal or O-ring that prevents moisture from entering the lens housing.

Step 2: Inspect the Headlight Lens

Now that the lens cover is out and free take a few minutes to inspect the cover for any damage to the lens housing or seals. Look for crack or warping that may indicate leaks. Identifying these trouble areas may help to extend the life of your headlight lenses and give you more time in between cleanings.

Method One: Soap and Scrub

The first method for cleaning the lens is using warm water and mild dish soap. With the headlight lens removed, submerge the lens cover in a bucket or large sink filled with the warm water and soap. Like your dishes, this will allow the soap and water to dissolve any built-up hazing, yellowing, and grime on the inside of the lens. Make sure you remove any bulbs or electrical components before submerging the lens.

After the soak, you will need to scrub the inside of the lens. You can rub the inside of the lens multiple ways. I recommend using a magnetic fish tank cleaner (>>> Check on Amazon). The magnetic cleaner will make it easy to clean the entirety of the interior of the lens without trying to stuff a rag or sponge through the small bulb holes.

My other recommendation is to use a long bottle brush. This method makes it a little harder to reach all the corners and edges but is still easier than sponging. When using the bottle brush, apply light pressure to make sure you don’t scratch or score the inside of the lens.

After scrubbing, allow the lens to dry. Lay the lens in a way that any remaining water will drain toward the edges or out the bulb holes. After drying, replace the headlight lens in the vehicle frame and reinstall with the mounting bolts.

Method 2: Methanol Bath

This second method is slightly more dangerous than old-fashioned soap and is excellent for cleaning the inside of your headlight lenses. Methanol is a highly flammable solvent, so make sure you keep away from flames, lit cigarettes, etc. When selecting your methanol be sure to get laboratory grade that is a 99.95% methanol solution. You will also need a heat gun( >>> Check price on Amazon) for later on in the process.

Using a cooking grade measuring cup, pour 1/4 pint (8 tablespoons or 1/5 cup) of the 99.95% methanol into the facedown lens. Swish the lens around for 1-2 minutes, being sure to coat the entire surface. Pour out the solution and use a heat gun to remove the excess. You can also allow it to sit and evaporate naturally, which will take up to 3 days.

The result is a beautiful showroom shine without damaging the reflective silver surfaces of your headlight lens. The extra time, tools, and solutions in this method make it a little further out of reach for less experienced home mechanics, so make sure you are comfortable and knowledgeable of all included materials before proceeding with this headlight cleaning method. After the job is done you may also want to clear coat your headligts.

The Perfect Headlight Shine

Knowing how to clean the inside of a headlight lens has more benefits than I listed today. So, whatever your reason for restoring that perfect shine, you now know two excellent ways to take those dingy lights and turn them into brand new looking beauties.