Can You Clay Bar A Windshield? 5 Other Deep Cleaning Tips:




Deep cleaning a windshield

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In every detail job, the very last step in a professional detail is usually the windshield. It’s been a huge pain point for me in the past and unfortunately, I’ve made it take too long and be way more work than it should be. I’ve learned the hard way that, like everything else in detailing, it’s all about the preparation and attention paid during the wash that makes all the difference.

It’s perfectly safe to use a clay bar on your windshield. Clay bars are intended to be safely used on paint and glass is a surface that’s much harder to scratch. There are times when a regular wash won’t remove contaminants like bugs, overspray, and fallout. This is when a clay bar should be used.

When you’re washing your car, take a second to feel the glass. Does it feel rough? Similar to paint, the windshield can have environmental contaminants embedded in the surface. In these cases, you may want to break out the clay bar to safely pull these contaminants out- leaving your glass smooth to the touch.

Deep cleaning a windshield

How to use a clay bar on a windshield – will it scratch glass?

In order for clay bars to be able to do their jobs and do them without scratching, they need lubrication. If lubrication is missed, clay bars can become sticky and adhere to the surface. Unfortunately, this can cause light marring or even scratches. But avoiding scratches is a simple step in this process.

Lubricating your clay bar can be achieved in two ways. You can use the car wash soap left over from the wash as a lubricant and “wipe” the windshield with the clay bar. This is my personal favorite method as it saves a bit of time and product. Not to mention that at this point the vehicle hasn’t been dried yet so you can use your pressure washer to rinse the soap off after claying the glass.

However, if after you’ve clayed the windshield there is still some roughness to the surface, you can use another method of attack without having to backtrack and rewash part of the car. 

The second method in this process would be to spray the windshield with a dedicated clay lube and again, “wipe”  the windshield with the clay bar. I say “wipe” because you’re not going to apply heavy pressure to the clay. Clay works best with light pressure and quick passes. If you prefer to use a dedicated lube, I still recommend doing this before the car has been dried.

Deep cleaning a windshield

After, you would then rinse it off with the pressure washer to ensure that all the lube is off the car.  You’ll know you’ve gotten all the contaminants out of the glass when you no longer hear or feel the roughness that you did in your first passes. Examine your clay bar after you’ve completed a small section. If your clay bar has gotten darker, fold it in half and flatten it out to use a part of the bar.

If you accidentally drop it on the ground, throw it away. I know it seems wasteful but the last thing you want is for that clay to have picked up some small piece of dirt and put a deep scratch into your glass or clear coat. 

Want to learn more about clay bars? Check out this article:

Other ways to make your car windows crystal clear:

Sometimes claying alone isn’t enough to satisfy the OCD we experience while detailing our vehicles. Perhaps the glass has something really baked on and clay isn’t doing the trick, or maybe the glass just has some marring from the wiper blades or just everyday use. What do you do in those situations? Here are a couple of tricks I like to use when I need a little extra help:

Deep cleaning a windshield

Scraping gunk off your windshield with a razor blade

Now don’t freak out, this is perfectly safe as long as you pay close attention and follow proper technique.

First, I’ll make sure the windshield has plenty of lubrication. I’ve used clay lube, car wash soap leftover from the wash, or even glass cleaner. Then I take a brand new razor blade out of the package making sure the blade is free of any manufacturing defects and insert it in a razor blade holder.

Then, hold it at a 30 to 40 degree angle off the glass and scrape the windshield with quick up and down strokes with light pressure. This is a really good trick but plenty of caution needs to be exercised or else your heart is going to drop into your toes (ask me how I know). You may even want to save yourself the headache and do this step even before you take clay to the windshield.

Polishing the windshield to remove stubborn dirt and stains

This second trick I use after the glass has been cleaned and is completely spotless. If after the glass is clean I notice there is some minor marring on the glass I’ll take my dual action polisher and make a couple of quick passes.

Glass is much harder than clear coat so you have to use a more aggressive pad, typically a glass specific microfiber cutting pad is the correct tool for the job since they have less padding allowing more of the torque from your machine to reach the glass, combine this with a glass specific polish like CeriGlass and you can expect some really impressive results.

If you don’t have any glass-specific polishes you can use a regular cutting compound in a pinch. 

Making your windshield easier to clean with a rain repellent

Your windshield is looking pretty good now, isn’t it? Let’s take one final step to bring this job to the next level. If you guessed I was talking about rain repellant, you would be right. This is really going to make your life easier, especially the next time you get caught in a torrential downpour. Today you have an incredible amount of options when it comes to a layer of protection on your windshield.

On the budget end of water repellant you’ve got Rain-X, they’re the OG in windshield water repellent products and still the choice of many automotive enthusiasts and detailers alike. The biggest downside to Rain-X is longevity, I’ve found it doesn’t last longer than a few weeks. But at the cost, it’s not breaking the bank even if you need to top it off every month or so.

For those of us that prefer to spend a little more time and money upfront for less maintenance in the long run, there are glass coatings like Q2 View and Flyby Forte. The biggest drawback to applying a coating is the cost, they are typically four times the cost for about one tenth the amount of product, but can last several months in between applications. You’re almost done now.

What good is a squeaky clean windshield if your wiper blades are going to smudge all the dirt and grime back into the windshield that they picked up before you cleaned it? Take a microfiber towel, spray a few squirts into the towel then pinch the far end of the wiper blade with that towel and pull it toward you. Now that the outside is perfect it’s time to move onto the inside.

Deep cleaning a windshield

What causes the oily film on the inside of a windshield?

Do you ever feel like the inside of your windshield is constantly covered in an oily film? What could be causing that? There are actually a few things that could be contributing to this film build-up.

In a new car the most likely suspect is that your car’s plastic interior trim might still be off-gassing (typically referred to as “new car smell”. Other causes could be smog if you live in a big city, a possible coolant leak from your heater core, or smoke getting trapped in the vehicle. 

If your car is newer and the interior is still off-gassing, there isn’t too much you can do to prevent this except to park your car in the shade or ideally the garage. If you have to park in the office parking lot, your best option is to limit the amount of heat that builds up in your car as that speeds up the off-gassing process.

A few practical methods of reducing the interior temperature are to open your windows slightly to allow fresh air in and stale air out of the vehicle and reduce the U.V. rays entering the vehicle. The cheapest solution, in this case, is a sunshade like this.

A more permanent solution is to ask your local tint shop to apply a ceramic window tint. Ceramic window tint can block between 45% and 50% of solar heat from entering your car. Make sure you check with your local laws as most ceramic tint used on windshields is rated around 70% and may be illegal in your area. 

If you suspect your heater core is leaking causing your oily film concern, take a look at your coolant level. If it’s low you may have a leak, however, this isn’t a guaranteed diagnosis. Wipe the windshield with your finger and smell it, if it smells sweet there’s a pretty good chance your heater core needs to be replaced.

This is never fun, even on the most accessible heater cores this job can be a bit intimidating to undertake. There is no shame in farming it out to a professional with experience with your make and model vehicle.

There isn’t much you can do to prevent oily residue on your windshield if it’s caused by cigarette or vape smoke except to stop smoking in your vehicle. I had a customer a few years back that vaped in his car so much that the windshield was tinted and incredibly hazy, it was so bad I could barely see out of the windshield. I’m not quite sure if that complied with our local windshield tint laws. 

A wild card cause of your hazy windshield might be the products you apply to the dashboard (I’m looking at you Armor-All). Make sure you avoid applying anything to your interior that leaves the leather or plastic looking wet and shiny.

Not only do they attract dust and contribute to hazy interior glass, but they also make driving hazardous. The last thing you want when you need to perform an evasive maneuver is lubrication on your pedals, steering wheel, or shifter.

Deep cleaning a windshield

How to get rid of haze on the inside of your windshield

Although annoying and unsightly, cleaning hazy windows isn’t all that difficult or time consuming. But there are a few techniques and products to learn about and use. Most often it’s best to make two separate passes to achieve perfection. If there is any adhesive on the glass, you’ll want to tackle that first to avoid clogging up your glass cleaning towels.

Speaking of towels, you’ll want two different microfibre towels. The first one should be a medium GSM (grams per square meter) towel- waffle weave towels are great for a first pass. I find it easiest to go through the passenger side resting my left knee on the passenger seat and left hand on the driver’s seat.

This way I can wipe across the entire windshield without stopping, I’ve realized that by stopping halfway across the glass you can miss spots or leave streaks. It’s also important that you spray glass cleaner onto the towel instead of the windshield itself on the interior, this way you avoid getting glass cleaner overspray on the dashboard you just finished detailing.

After your first pass with the medium GSM towel switch to a low GSM towel to remove any streaks leftover from the first pass.

Can you use Windex, vinegar, or rubbing alcohol on car windows?

When choosing what products to use on your glass there are a few considerations to be made. Steer clear of anything with ammonia in the list of ingredients, this excludes most formulas of Windex and other household window cleaners, ammonia is not safe to use on window tint and can cause bubbling, haze, and discoloration.

Some people recommend mixing your own cleaner and using vinegar as the base, the results may be alright, but then your car smells like vinegar until it dries. I’ll gladly pay the $10 for a good glass cleaner that’s safe and won’t stink up my interior.

When tackling adhesive on the inside of the glass, rubbing alcohol can be an incredible product to keep in your arsenal. It won’t damage the glass or tint and since it evaporates quickly it won’t leave streaks either.

2 responses to “Can You Clay Bar A Windshield? 5 Other Deep Cleaning Tips:”

  1. Bruce Bealor Avatar
    Bruce Bealor

    I’m looking to “remove” some scratches from a plastic like window in an older convertible. It appears the previous owner tried to clean the window with wet sanding. Any hope?

    1. Canadian Gearhead Avatar
      Canadian Gearhead

      If the plastic was soft enough to allow visible scratches from sanding, it should also be soft enough that polishing will remove them. I’d say there’s hope!


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