Best Tips: How to Clean Car Windows Without Streaks

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Car owners know only too well just how difficult it is to get the glass surface spotless. More to the point: “streakless.” While your car’s windows need to look clean for your entire vehicle to look good, there are important safety and visibility reasons for that, too. Today, we’ll explore this sort of window treatment and share the best way to keep them clean and clear of unsightly streaks.

Understanding the Problem

The first step to understanding the problem is to identify the causes. It’s not rocket science or even hard work, but the causes can be overlooked when giving your car a good cleaning. We pay a lot of attention to paint, tires, and upholstery, and even our steering wheel, but often consider car glass “clean” after an exterior wash.

Causes of Streaking

There are three key causes of streaking on automotive glass windows:


1. Improper Cleaning Techniques

There was a time where it was thought that using newsprint or paper towels were effective tools. In general, newspaper can be acceptable for regular glass, but not auto glass. Residue from the ink may not be visible on say, a mirror in the home, but can be an issue when looking through a car windshield. Since newsprint is not considered high quality paper, it can leave link or other fibers behind.

For much of the same reasons, paper towels can be even more problematic. When wet, they loose their structural integrity even faster, and as an even lower quality paper, can be an even worse lint contributor. This can also lead to an uneven finish when attempting to wipe the cleaner and dirt away.

2. Low Quality or Inappropriate Cleaning Products

A good quality glass cleaner designed specifically for automotive window glass use is a very good idea. Spray it right on the exterior side of the window. Be sure to cover the entire window. When addressing the inside of your front windshield or other interior windows, use caution around upholstery and trim. The cleaning agent may not be the best for those surfaces.

Avoid regular household glass cleaners. They may be just fine for mirrors or other surfaces inside your home, but not so much for the windows of your car. Auto experts agree that dirty windows need special treatment with specialized glass cleaning products.

Ammonia-based cleaners exist. If an ammonia-free cleaner is of interest, maybe a homemade glass cleaner is for you. The best thing to use in that case is a vinegar solution. Vinegar can help dissolve even the toughest residues. Mix equal parts distilled water and vinegar in a spray bottle. Spray the solution onto the glass and wipe it off with a clean microfiber towel.

A homemade car window cleaner is a good environmental choice, but it could save you some money, too!

3. Environmental Factors

How you clean your glass is important, but where you clean it is even more critical. If you have a garage in which to work, that is ideal. If you attempt to clean your car’s glass in direct sunlight, it will be very hard to stay ahead of the streaking.

The key reason is how quickly the glass can heat up. Even on a mild day, a car will quickly absorb heat. After all, it is like a small greenhouse. When the inside of your car gets hot, so will the exterior windows. Whether you’re using a generic glass cleaner or one of the best cleaners designed for automotive use, the solution will simply dry too quickly. “Quick dry” is not your friend and will leave behind pesky streaks.

In all cases, be sure to read the manufacturer’s instructions. They know their glass cleaners, so pay attention to any nuance they share to make sure you get the best results possible. That will also help protect related surfaces.

Types of Residue

Any buildup of residue can impact any surface of your car. Getting perfectly clean glass is no exception. Residue is the primary reason for streaking, so making sure to not leave any is critical. With a little effort, you can make sure these residue types are fully eliminated:

Hard Water Spots

If you live in an area with hard water (high mineral content) you understand the stubborn stains. Cleaning car windows can be a challenge if you don’t get the water off the surface quickly. When washing, get the windshield of your car and the sides of windows dried as quickly as possible. Once dry, you can then tend to improve on the newly clean windshield.

Dirt. Grime. Film Buildup.

These are grouped together since one leads to the other, which leads to the next. The simple task of keeping your car clean is the first step. However, if you have a long streak of dry weather, you may not feel the need to wash and detail your vehicle. That’s trouble for your glass.

From brake dust to pollution in general (don’t even talk to me about bird droppings) glass can get dirty – even without the road spray from rain. The good news is that in about 5 minutes, you can go around your car, cleaning all exterior sides of the windows. If you have another 10-15 minutes to climb around inside, you can get the inside of your windshield and the interior sides of the glass.

A frequent “quick clean” can avoid the buildup that causes unsightly – and dangerous – streaks.

Impacts of Streaks on Visibility

Safety. It is what outranks all other issues. It can be at risk when you are not able to clearly see outside your car’s windshield. Looking through the oily residue that comes from road grime is no fun, either. Especially when looking into the sun. You know the look.

The glare associated with glass streaks can be a serious problem. Even new wiper blades are of minimal help, much less, worn ones. A simple trick when cleaning your car is a quick treatment of the windshield wipers. A simple wiper treatment is to wipe down the business edge of the wiper. Cleaning the glass is one thing, but taking a moment to lift the wiper and clean the edge that contacts the glass will help tremendously.

Gathering the Right Tools and Materials

With any automotive detailing project, it is always a good strategy to collect what you need before you start. Here’s a suggested list of products you’ll want to have close by, depending on the severity of your cleaning task.

Dry Microfiber Cloth

Not any clean cloth will do. The microfibre cloth is one of the best detailing tools you can use. It has physical properties that really capture dirt and works well on all surfaces, especially glass.

Glass Cleaner

Whether you are using a regular commercial product designed for automotive glass, a non-ammonia glass cleaner, or a homemade cleaning solution, choose the one that works best for you and get it ready. Having and empty spray bottle (more many of them) at the ready at all times allows you to keep you favorite products within easy reach.

Plastic Razor Blade Scraper

Agreed, this is an odd suggestion, but hear me out. You won’t always be doing a light touch-up. There will be times where substantial build-up or accidental debris (I’m looking at you, birds) will cause unusual levels of grime. Rather than take all afternoon scrubbing, give it a light “suggestion” with a plastic razor blade scraper. Once the bulk of it is removed, it becomes much easier to finish normally.

Window Cleaning Squeegee

Not meaning to pick a fight, but a squeegee may be right for you. There are some who use one on the interior side of the windows, in addition to the outside. This is a personal preference call. Personally? I use a squeegee on an extended arm handle for a quick clean of the windshield. Depending on the level of rain-induced grime, I sometimes use it on the side windows and rear window.

Admittedly, it’s not a detailer’s best work. However, given how quickly it can make the glass look pretty nice, it’s a fair investment of time for me. Your mileage may vary.

Preparing the Windows

As mentioned previously, having the car parked in the direct sun is a no-go. Pull it into the garage or at least find a shady area to prevent any challenges associated with your cleaner drying much too quickly.

Generally, your usual careful wash of the entire car will get the glass “clean” enough to… well… clean it. Under extreme conditions, extra effort may be needed. (See plastic scraper comments above.)

Pro Tip

You know that thin line of dirt that’s visible along the edge when you crack your side window? When cleaning the windows, remember to lower each side window slightly and get that line of dirt along the edge. Your future self will thank you the next time you need roll down your window.

Proper Cleaning Techniques

It’s best to use the “Two Microfiber Rag” approach. This allows you to benefit from the best traits microfibre towels have to offer. Start with the clean side of Towel 1. The gripping capabilities will help you get that grit and grime. Towel 2 then becomes the polisher, getting any minor residue from the first wipe of Towel 1.

There are many differing opinions about wiping patterns. Straight, then 90 degrees and straight again. There’s the “S” pattern, and of course circular. There are many variables if you consider vehicle size, your height, your strength, arm length… you get the idea. Try them all to see what gives the best results. Me? Circular. It’s like a giant polisher and I get very good results.

Don’t forget the corners or any exterior crevices. Take your time and get even the odd places. You’ll notice of you don’t.

Exterior Glass

Spray your chosen glass cleaner evenly on the window surface. If you have significant grime or bug buildup, leaving it sit for a few minutes will help to dislodge the debris. For the windshield and the rear window, consider doing one half at a time to prevent too much drying. Side windows should be done one at a time.

Interior Glass

On the inside, it’s best to spray your cleaner on Towel 1, then wipe. If you spray directly on the glass, you then need to worry about cleaning up the overspray. Over time, this can save you money, too, by reducing waste.

Finish up with Towel 2 and you’l have a crystal clear view of the road!

Dealing with Water Spots and Hard Water Deposits

As mentioned above, if your water supply is high in mineral content, spotting is a bit more of a challenge. Using a white vinegar and warm water solution or a commercial lime scale remover is your best strategy.

Use a soft cloth to wet the affected areas. Let it set a few minutes to loosen the deposits. With a clean microfiber cloth, scrub the spots using a circular motion to attack from all directions. When you rinse, use distilled water for the best results. Dry the glass quickly and thoroughly for a crystal clear result.

Preventive Measures for Maintaining Clean Windows

Just as you wash your car frequently to prevent excessive dirt and grime buildup, so should you clean your windows. In fact, giving the exterior glass a quick clean in between complete wash/detail sessions is your best bet. The rest of the vehicle may only be slightly dirty, but windows can show dirt much more quickly.

As we’ve discussed, avoid washing your vehicle in direct sun. Even moderate temperatures can rapidly heat the glass and lead to quick dying and those pesky streaks.

Finally, if you don’t have access to park in a garage, consider a car cover to provide overall protection. For a moderate investment and only a few minutes each time you park, you can put a protective barrier between the elements and your car’s surfaces.

For More Information About Windows and Glass


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