Let’s continue the discussion of interior detailing from the last few months, as this is a complicated topic. The key to successful interior detailing is understanding the materials and how to care for them so as to bring to bear the most efficient techniques to get the job done.
The standard interior detailing process generally includes these steps:

  • Remove customer belongings
  • Vacuum and air purge
  • Check headliner
  • Clean vinyl and plastic panels
  • Clean seats
  • Clean carpets
  • Dress vinyl and plastic panels
  • Condition leather
  • Clean interior glass
  • Deodorize as necessary

In the November issue, the discussion focused on care of vehicle carpeting. We looked at the chemicals and equipment that are necessary to effectively clean carpeting, as well as some recommended procedures. We also dove into the different types of stains that are typically involved, and how to remove them. Then we finished up with drying the carpets, as well as briefly touching on additional carpet services like deodorization and applying fabric protection.
Now, let’s continue by going over the final steps in the interior detailing process, including glass cleaning and conditioning of interior surfaces.


Arguably the detailer’s least favorite thing to do is work on cleaning windows, not so much because it is a difficult task, but more because it can be so frustrating. It is amazing how many customers will overlook a beautifully and completely detailed vehicle upon noticing one streak in the windshield!
Often, obtaining streak-free windows is more a matter of the technique and equipment used, than the technician’s best intentions. I have witnessed professional detailing technicians clean the same windshield several times and still fail at achieving streak-free results, and it has nothing to do with the technician’s prowess, but more to do with the chemicals, towels, and technique being used.
So, let’s talk about the different things that can cause problems with window cleaning, and find solutions to those problems.

Wiping Instrument
The first, and probably most common area needing correction, is the actual towels or other wiping instruments that are used for window cleaning. Most important, the towels that are used for window cleaning need to be dedicated to only that activity. They must also be cleaned and stored separately. Even the used window cleaning towels awaiting laundering should be in a separate bin away from towels used for other purposes, like wax removal and interior cleaning.
If you are currently mixing your window towels in with others, they are likely contaminated with cleaners, waxes, and residues that will cause streaking while wiping windows, no matter how much the combined towels are washed. It is time to set these used, contaminated window towels aside and buy a whole new batch of towels that will be dedicated solely for use on windows and kept completely separate from all other towels.
Secondly, the type of towel being used may be causing problems. There are a number of window cleaningoptions available from the manufacturers of towels for detailing. The type of towel that is going to work best for you is partly a matter of your exact procedure for glass cleaning, as well as personal preference. It is worthwhile to experiment with several types of window towels, as there may be a type out there that makes your window work much easier, and helps reduce streaking issues.
Thirdly, the number of towels used for window cleaning can also impact the results. Most detailing professionals agree that two towels are needed. The first towel is a “wet” towel that is sprayed with or collects the glass cleaner sprayed directly on the window, and this towel cuts through the contaminants on the glass. The second towel, typically dry, follows on by wiping the glass to a streak-free (hopefully) finish.
In the most extreme cases of particularly grimy windows, the second towel may need to be damp with glass cleaner, followed by a final wipe with a third towel. And, sometimes, it is simply necessary to clean really bad windows twice with two sets of towels each time.
Another recommendation is to fold the window towel twice, so as to create eight potential surfaces of use with the same towel, and to switch out to a fresh side while making one’s way around the vehicle.
Some technicians are finding that using a terry or microfiber pad as the first wiping instrument greatly helps to cut through window grime, after which the final wiping with the dry towel goes rather smoothly. In some cases, a stronger appliance like a melamine sponge may be necessary to cut through the worst window grime—finger prints, nicotine residue, and dog slime.

Window Cleaning Chemical
Another important factor in streak-free window cleaning is using the correct kind of chemical. It should be a glass cleaner that is designed specifically for automotive glass, and should be safe on aftermarket tint that is sometimes applied to the inside surface of the window. For example, some household window cleaning agents have an ammonia base, which is not recommended to automotive window tint. Many automotive window cleaning agents, on the other hand, have isopropyl alcohol and other tint-safe cleaning agents as their base.
Ready-to-use window cleaner is a common choice, but for those who do a lot of window cleaning, a glass cleaner concentrate may be a money-saving solution. Concentrated glass cleaner, when properly diluted (according to the instructions on the label!), should work exactly the same as ready-to-use glass cleaner. It is recommended that distilled water, available at most grocery stores, or otherwise treated water, be used to dilute glass cleaner concentrate, as this will lead to a purer cleaning agent, free of excess minerals and other contaminants that may be present in tap water.

Glass Cleaning Procedural Tips
First, since we are working on the interior of the vehicle, it is not necessary to clean the exterior windows if there is still work to be done on the outside (like applying wax, sealant, or coating). In fact, in the overall detailing process, I recommend that the exterior glass is absolutely the last thing that is touched.
Another tip is to always start with the windshield, when the towels are cleanest. This will help ensure that the windshield ends up being streak-free, a critical consideration because that is the first window that most customer will inspect upon getting into the car after the detail.
For any roll-down windows, roll them down about one-third of the way and clean the top edge of both the inside AND outside of the window, then roll it up and clean the rest of the interior glass. By doing so, it will not be necessary to lower the windows upon the later cleaning of the exterior glass.
Finally, remember that “interior glass cleaning” also includes such glass or clear surfaces as:
• The rearview mirror
• The vanity mirrors in the visors
• The sunroof and other ceiling glass
• The clear plastic gauge cluster above the steering wheel
• Any display screens

The Glass Itself
It is critical to be familiar with the variables that one may be confronted with as far as the “glass” surface itself is concerned. First, realize that there is a difference between factory window tint and aftermarket tint. Factory window tinting is a coloration that is infused into the glass itself and cannot be removed or damaged. On the other hand, aftermarket window tint is actually a plastic film that is applied by a shop sometime after vehicle manufacture. It could be as a dealer-applied add-on or an aftermarket tint shop. Further, on the exterior surface of the glass, there may be aftermarket clear, stone-chip protection film applied.
It is for this reason that abrasive scrubbing appliances like steel wool or razor blades should generally not be used on interior glass, and certainly not before thoroughly checking for the presence of aftermarket tint. Some detailers find it easier to clean exterior glass with steel wool in areas where grime and water spots are common, but these technicians never use steel wool that is stronger than “quadruple-aught” (that is, four “zeros” or 0000 steel wool). (“Aught” means “zero”.)


Plastic and Vinyl
There will always be a debate among some detailing professionals about the appropriateness of dressing freshly cleaned plastic and vinyl surfaces, like the dashboard and door panels. It really depends on the customer preference. I personally know very successful detailing professionals that have never dressed plastic or vinyl, and none of their customers complain. Others automatically included dressing of virtually every interior plastic and vinyl panel.
If your shop does dress vinyl and plastic, be sure to use only water-based dressings on the interior. Also, use a dressing that is designed specifically for automotive vinyl and plastic. Moreover, a great way to finish off the interior dressing is by wiping the freshly dressed panels with a clean interior towel, thus removing excess dressing that may feel greasy or look too shiny to the customer. This final wipe tends to leave the panels looking clean and new with a nice, even satin finish, as opposed to an unnaturally glossy finish. The final wipe also gives you a chance to wipe up any stray dressing that got onto brightwork or other “no-dressing” surfaces.
Make sure that dressing never goes on these surfaces:
• Steering wheel
• Gear shift
• Parking brake handle
• Foot pedals
• Screens and brightwork

Dressing Vinyl and Rubber Mats
It is generally recommended that these mats should never be dressed, because of the danger that the dressing will transfer to the bottom of the driver’s shoes, thus causing slippage while using the foot pedals. Moreover, even the customer shoe bottoms might become slippery, causing a slip-and-fall upon exiting the vehicle.
Some argue that the dressed mats can be sufficiently wiped of excess dressing. Nonetheless, even the thinnest layer of dressing, once moistened with a damp shoe bottom, will be reactivated and cause slipperiness. The best practice is to simply never dress floor mats, period.

Conditioning Leather Seats
This was extensively covered in an earlier column (See Auto Laundry News, October 2022) that discussed vehicle seat care. In review, use only conditioner that is formulated specifically for use in automotive leather. Apply liberally, and wipe off the excess with a clean interior microfiber towel.


There are companies that offer ceramic-infused protective coatings for use on interior surfaces, like leather, plastic, vinyl, fabric, and carpeting. This is certainly a viable
service that should be priced as a premium add-on or part of a new vehicle protection package. Special training might be necessary to learn application methods, but it can be
a profitable addition to a standard detailing menu.


Once the interior of the vehicle is completely detailed, return all of the vehicle mats, making sure that they are properly secured and anti-movement clips are present.
Next place bagged customer belongings inside the car, perhaps on the passenger seat where they will be immediately noticed by the customer. Larger belongings could be placed
in the trunk or rear compartment of an SUV.
At this time, it is recommended to do a final touch-up vacuum to catch any leftover lint or sand or other particles that may have appeared during the previous detailing steps.


Well, if you have been following this series on interior detailing, you can see that it is a complicated process involving many steps and variables. Although I have endeavored to cover all of the issues, I am sure someone reading will mutter, “well you forgot to talk about such-and-such.” I welcome your comments at the e-mail below. I hope this series was of assistance.

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 prentice@detailinprogress.com.