Use Steel Wool to Clean Glass: Windows & Windshields Sparkle!

Road tar, tree sap, squashed bugs, and water spots on your RV windshield (or any windshield) can be a pain to remove. That’s why we’re sharing a tip we’ve been using on all of our vehicles (including both of our motorhomes) for over 25 years — cleaning the glass with steel wool.

Yes, you can actually clean windshields with steel wool, but there are a few things you’ll want to keep in mind. Let’s take a look at the process of using steel wool to clean glass.

 

How to Use Steel Wool to Clean Glass

Using steel wool to clean your windshield is a more aggressive option than simply using glass cleaner alone, so it’s a good idea to keep a few things in mind when using this method.

Before we lay out the items you’ll need and the steps to clean your windshield glass with steel wool, we want to clarify that we’re referring to automotive glass in this post. Some RVs have windows made of polycarbonate, plexiglass, or even plastic. Side-view mirrors and rear windows on some convertibles are often made of materials that are softer than auto glass, too.

So before cleaning a window with steel wool, make sure you’re cleaning automotive glass — the type used in motor vehicles that’s designed not to crack into dangerous shards if it breaks. It’s tempered and/or laminated to protect occupants in the event of a crash, and steel wool won’t harm it.

Also, please note that we only suggest doing this on the outside of the glass. Not only isn’t it needed inside (it’s unlikely you’ll ever have road tar or tree sap on the interior) but it will also avoid any bits of steel wool ending up inside. More on that below.

On a related note, use caution when storing steel wool. Surprisingly, steel wool is highly flammable, so it’s important to store it safely with this in mind.

Items We Use to Clean Glass With Steel Wool

• 0000 Steel Wool 
• Rain-X 
• Invisible Glass 
• Microfiber Cloths  or a couple of clean rags
• An old sock (to apply the Rain-X)

Make sure you’re using the finest grade steel wool — 0000. Do not use any type of scouring pad intended for cleaning pots & pans. 0000 steel wool is the super fine grade that cabinet and furniture makers use. I remember watching in amazement as a kid as my Dad used 0000 steel wool to buff a piece of furniture between coats of varnish. It seems counterintuitive that it wouldn’t scratch the finish, but it won’t!

Use a Steel Wool Pad to Polish the Glass

We learned this method from an auto detailer. It’s a trick of the trade for getting off just about anything that’s stuck on the glass including some pretty stubborn water spots.

If your windshield is really dirty, it’s a good idea to wash it off before using the steel wool to remove bug bodies, tar, sap, and anything else stuck to the window. Not only will this prevent any debris, such as sand, from scratching the glass, but it will make it easier to see where the worst tar, bugs, or tree sap are located.

Note that when using 0000 steel wool, there’s the potential for tiny bits of it to break off during the cleaning process. If left in place, it can rust and leave small marks on surfaces. We’ve never experienced this issue in all these years of using this technique on our RVs and cars. For anyone with this concern, using bronze wool to clean windows would address that issue.

As always, we recommend trying any new product or method in an inconspicuous area first.

Use a single fine steel wool pad to rub all over the windshield using a bit of elbow grease, especially in areas where things like sap have accumulated. It doesn’t matter whether you rub in circular motions or back and forth.

Continue polishing the glass using the steel wool to clean off anything that’s on it, removing all of the microscopic dirt and debris on the windshield.

Note that as long as you keep your steel wool dry, it won’t wear out, so you can use it over and over again. If you do get it wet, it will rust, so you’ll need to throw it away if that happens. Speaking of which…

PRO TIP: Consider wetting your steel wool pad thoroughly with window cleaner before using it on the windshield. A wet steel wool pad will do an extra-good job of cleaning off stubborn stains. Just be sure to throw the pad away after you get it wet since it will rust. If you’re okay with using up a single steel wool pad for each cleaning, this is an excellent way to super-clean the glass.

Apply Rain-X To The Glass

Once you’ve finished using the steel wool to polish the glass to remove all of the dirt and debris, apply some Rain-X to an old sock, a small rag, or a microfiber cloth. Apply the Rain-X liberally, but avoid getting it on the paint of your car or RV.

When applying the Rain-X, use a circular overlapping motion, thoroughly covering every surface of the glass just as you would apply car wax to paint. Be sure to cover the entire surface. Just like wax, you should be able to see where it goes on as it leaves a bit of a film or haze.

Allow Rain-X To Dry For About 10-15 Minutes

Allow the Rain-X to dry for about 10-15 minutes. It will dry to a hazy film, similar to what a thin coat of car wax looks like when it dries on your vehicle’s paint.

Use a Wet Rag to Clean Off the Rain-X

The Rain-X instructions say that once it dries to a haze, you can either wipe it off with a dry cloth, or “sprinkle” some water on it and use a “paper towel” to wipe it off and dry the glass. We’re here to tell you that those instructions suck. We love Rain-X, but they have that part all wrong.

After rubbing a dry cloth or paper towel like crazy to remove it, you will still be left with a hazy film. Here’s the right way to remove Rain-X:

PRO TIP: To easily and thoroughly remove Rain-X, wet a clean rag or microfiber cloth. You don’t want it to be dripping wet, but fully wet and wrung out. Use the rag to wipe off the entire windshield thoroughly. Then finish up with a dry cloth.

Clean the Interior Glass

Our favorite glass cleaner for the interior of any vehicle and for home mirrors and windows is Invisible Glass. It’s far superior to any other glass cleaner we’ve ever used.

We’ve been using Invisible Glass for many years and have found that it does a far better job, without streaking, to give us a better view. We prefer the Rain Repellent version, since it does an awesome job of helping water bead.

This is the method we used to super clean the windshields on all of our vehicles for years. It leaves us with sparkling glass that stays cleaner longer. Thanks to Rain-X, Invisible Glass, and 0000 steel wool for helping us keep our vehicles super clean.

You can watch us using this method to clean the windshield on our CR-V:

Will Steel Wool Scratch the Glass?

In well over 25 years of using this method to clean the windshields on all of our cars and both of our RVs, we’ve never experienced an issue with scratching. However, we’ve read comments about steel wool scratching glass or leaving swirls that are mostly visible at night or in the glare from oncoming headlights.

This shouldn’t happen because glass is harder than steel wool. Think about the fact that you can use a steel razor blade to scrape glass clean without scratching it. It seems counterintuitive, but it’s explained by something called the Mohs scale of hardness, which refers to the ability of a harder substance to scratch a softer material.

Glass is actually harder than steel wool. Typical window glass rates around 6.5 on the Mohs scale vs. only about 5.5 for a typical knife blade. For comparison, a diamond is a 10 on the scale, which is why it can scratch and cut almost anything.

And again, we’ve never seen evidence of this happening. Our Honda CR-V is over 21 years old and we’ve used this method on the windshield repeatedly over the years and never had a single issue, even at night.

But, here are a few thoughts on why people might notice fine scratches or swirls on their windshields:

1. Old glass that has been etched by acid rain could have a softer surface.
2. What appears to be fine scratches may actually be in a layer of wax on the glass and not on the glass itself. This could result from many years of running the car through an automatic car wash and opting for the “wax” treatment. That wax buildup is certainly not as hard as steel wool and could make it appear that there are scratches or swirls in the glass.
3. The glass may have had some other coating or sealant applied at some point (perhaps by a previous owner). Any type of coating would likely need to be chemically stripped from the glass before using the steel wool method.
4. Again, not all windows and mirrors are made of glass. Softer materials will scratch because they’re not harder than steel wool or brass wool.

To learn more about various ways to clean other types of RV windows, see our post on how to clean RV windows.

The best way to test your windshield is to use the steel wool in an inconspicuous area first and wait until you’ve been able to check the area in different lighting conditions (day and night) to be sure you’re happy with the results.

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