Continuing on with the “study guide” for the Detailing Certification Exams offered by the International Detailing Association, this month, let’s look at the exam module that focuses on vehicle glass and trim.

The International Detailing Association offers its Certified Detailer program to both members of the Association as well as non-members. The program currently consists of 10 exams that assess the taker’s background knowledge of detailing. This month’s column is one in an on-again-off-again series that is designed to present a study guide for those who are interested in taking the tests. Get more information or sign up for the tests at


Most detailers that I have spoken with have the same thing to say: “I hate cleaning windows!” Everyone seems to have a favorite towel or a favorite glass cleaner. The truth is, however, that most of us struggle with windows. And why is it that the first thing the customer notices about their beautifully detailed vehicle is the one streak in the windshield that you didn’t catch?

There are actually many variables that go into a successful window cleaning. These include, the chemical used, the towel used, the technique used, and the condition of the windows themselves.

First, it is important to talk about the glass itself. For example, factory window tinting is usually built into the glass as it is made, and thus cannot be removed regardless of the window cleaning methods used.

Aftermarket tinting, on the other hand, is applied by a local tint shop or at the dealer after the car is purchased, and is simply a plastic film that is placed on the inside of the window. The film can be damaged by such things as using window cleaner concentrate that is not fully diluted, using a window cleaner that is not designed for automotive glass, or using aggressive scrubbing techniques or tools like steel wool, harsh scrubbing pads, or brushes.


To achieve clean windows in the most efficient way possible, it is important to start with the proper materials. First, use a glass cleaner that is designed specifically for the automotive detailing industry. Some glass cleaners made for household use contain chemicals that can damage aftermarket tint on vehicle windows. Simply avoid the issue by using only glass cleaners from recognized chemical suppliers to the automotive detailing industry.

Over-the-counter household glass cleaners tend to be more expensive per ounce than cleaners designed for the professional detailing industry. In fact, many detailing chemical suppliers offer concentrated glass cleaners, which must be properly diluted before using. Once properly diluted, these cleaners cost very little per use. It is recommended to use treated water when diluting concentrated glass cleaner. That would be either distilled water (available in gallons at your local retailer), deionized water, or water treated by reverse osmosis. Diluting with these types of treated water will help reduce streaking because the glass cleaning solution is free of contaminants and minerals often found in tap water.

It is important to dilute concentrated glass cleaners exactly as recommended on the product label. Using window cleaners in their concentrated form or without full dilution may cause streaking and may damage aftermarket film.

Some technicians prefer to purchase ready-to-use glass cleaner, which works the same as a properly-diluted concentrated version, thus avoiding the dilution and water purity issues altogether. Other detailers prefer aerosol versions of glass cleaner.

Of course, no glass cleaning chemical is going to work well if the windows are too hot. Try to perform glass cleaning in the shade whenever possible.

Some operators choose to avoid the use of glass cleaning chemicals altogether by utilizing dry vapor steam to clean windows. The steam wand is held at a proper distance from the glass and the steam slowly and gently accumulates on the window surface, making is just damp and warm enough to then wipe with a clean, dry towel.

Caution must be used, however, because dry vapor steam, when applied too closely, can lift or damage aftermarket window film.

In fact, vapor steam is a great way to remove aftermarket window tinting, should the customer request this. A much more aggressive, concentrated effort is used with the steam wand in the case of tint removal. The nice thing about using steam is that it is often possible to remove the tint in one giant piece, with little or no adhesive residue remaining on the glass surface.


The next variable in window cleaning is the towel. Ask 10 professional detailers what they like to use and you will get 10 different answers. The answer list would include: terry, micro-fiber, disposable, newspaper, and huck towels. And I am sure there is someone reading this right now who likes a towel that I have not even mentioned.

All I will say is this: use the type of towel for windows that works best for you in your shop. It’s not so much what type of towel you use but how you treat it. Window towels should be kept separate from all other towels in your shop. They should be cleaned separately, stored separately, and disposed of in containers that keep them separate from other used towels. These procedures will help to reduce cross-contamination of the window towels with other chemicals and dirt that exist in the detailing shop. Such contamination can lead to streaks, no matter how well you clean the window.

If you are using the same towels in your shop for multiple purposes including windows, you are likely to have window streaking problems. Separate those towels!


Most glass cleaning challenges exist on the outside surface of the window. These include water spots, etching, overspray and other surface contamination, scratches, and pitting.

It can be difficult to distinguish between water spots and etching on the glass until it is actually wiped clean. Most water etching cannot be removed with standard detailing techniques. However, water spots that do not come off with normal window cleaning techniques can often be removed using more aggressive techniques. Choices here include water spot removing chemicals, polishing chemicals, and more aggressive scrubbing devices.

There are water spot removing chemicals that are specifically designed for removing water spots from glass. These are typically acid-based and require great care and proper use. Adhere closely to the label directions and wear your safety gear. Do not use other acid-based chemicals like wheel cleaner, as these chemicals use different kinds of acid that can actually cause damage to glass.

Most detailing chemical suppliers have a “glass polish” in their line of products. This type of chemical is designed to remove film, water spots, and minor etching that does not come off with normal glass cleaning. It can be applied by hand or carefully using a polisher with a foam polishing pad. Note: once a pad has been used for glass polishing, it should be dedicated to such, as glass polishes tend to be harsher than those used on vehicle paint.

Some technicians also like to use super-fine steel wool, such as “0000,” which is pronounced “quadruple aught.” (With steel wool, the less zeros, the stronger it is.) And detailing clay or surface prep towels can be effective at removing overspray and other surface contamination from the outside of the glass. A clean, new razor blade can be helpful for removing decals, tree sap, overspray, and other larger surface contaminants from the glass.

It is important to remember that these problems are all on the exterior of the glass, where it’s okay to use the more aggressive techniques. Interior window film can be scratched or marred by using glass polish, clay, or steel wool, so we generally don’t use those techniques in the inside of the windows.

Actual scratches in the exterior glass cannot be removed with polishing techniques normally used by detailers. Standard “glass polish” is available from most detail chemical suppliers. But these chemicals do not remove glass scratches, like the semi-circle arcs sometimes caused by the wipers. Removing glass scratches requires very specialized equipment, chemicals, and training.


A common part of the finishing touches on an exterior detail is shining up the vehicle trim pieces, which can be made up of such materials as rubber, vinyl, plastic, chrome, aluminum, and anodized aluminum.

Mist-and-wipe detail spray is great for touching up exterior surfaces like front grill areas and anything smooth and shiny. Chrome polish is generally best on chrome-plated metal pieces. However, chrome polish can actually scratch chrome-plated plastic pieces, which can instead be cleaned using glass cleaner or detail spray. Uncoated aluminum, sometimes called “bare” or “naked” aluminum, trim or wheels can be shined up with aluminum polish, which will turn black as it is being used on uncoated aluminum.

Anodized aluminum, often used as shiny metal trim around windows, looks like chrome. However, it may scratch if chrome polish is used. Also, anodized aluminum does not respond well to aluminum polish.

Anytime that compounds, polishes, waxes, or sealants are going to be used on the body panels, it’s a good idea to mask adjacent bare plastic, vinyl, and rubber trim so that it does not get stained from the paint chemicals. For wax and sealant application, it may be sufficient to simply apply an appropriate dressing to these moldings instead of actual masking.


There’s a lot more to cleaning glass than simply grabbing a towel and some glass cleaner. Likewise, exterior vehicle trim can be made up of several kinds of materials. The expert detailer will have the knowledge, equipment, and chemicals to deal with all of these surfaces.

Prentice St. Clair is an International Detailing Association Recognized Trainer and Certified Detailer. As the president of Detail in Progress Inc., he has been providing training and consulting to car washes and detail shops since 1999. He is available at (619) 701-1100 or