In this month’s column I’d like to continue the discussion of interior detailing that we started last month. As noted, many professional detailers, upon realizing how much work is truly involved in interior detailing, are either no longer offering the service, or significantly increasing their charges for complete interior detailing. 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:
1. Remove customer belongings
2. Vacuum and air purge
3. Check headliner
4. Clean vinyl and plastic panels
5. Clean seats
6. Clean carpets
7. Dress vinyl and plastic panels
8. Condition leather
9. Clean interior glass
10. Deodorize as necessary
Last month, I had enough space to cover only the first four steps. (See how complicated interior detailing is?) Customer belongings have been packed up, the vehicle is thoroughly vacuumed, the headliner cleaned as necessary, and all the plastic and vinyl panels in the car have been cleaned. Now, let’s continue with the next step of the interior detail process, cleaning the seats.
AUTOMOTIVE SEAT UPHOLSTERY
Upholstered vehicle seating requires specialized cleaning and care, just like any other interior or exterior surface. As a point of vocabulary clarification, the word “upholstery,” refers to the covering of a seat. Many think of the term “upholstery” as referring only to fabric seats. In truth, a seat may be upholstered in any number of materials. The word “upholstery,” refers to the outer thin layer of material that covers and holds in all the padding that gives the seat its shape. Upholstery materials typically used in automotive applications are: vinyl, leather, fabric, sport cloth, and imitation leather.
Often, more than one material is used to upholster a seat. For example, a common way for auto manufacturers to boost the perception of luxury is to describe their seats as “leather trimmed.” This typically means that some of the seat, usually the seat face, is upholstered in leather and the rest in vinyl. Only in the finer vehicles is the entire seat (front, face, sides, and back) covered completely in real leather. Similarly, some fabric seats have vinyl side panels and backs. Further, some leather seats have suede or nubuck inserts covering the center bolsters.
You will find that, in newer vehicles, the most common upholsteries are leather and sport cloth. Seats upholstered in vinyl are not as common anymore, but not extinct.
UPHOLSTERY COMPOSITION AND CARE
During the standard interior detail process, the seats will have been thoroughly vacuumed before they are cleaned, including any grit and debris from the seam areas. Spread the bolsters open with your hands and use a crevice tool and a soft nylon brush.
Now let’s dive into each of the upholsteries typically used in automobiles, and how to care for each one.
Real automotive leather starts with natural animal hide, typically cowhide. The raw hides are processed using procedures generically called “tanning,” which removes hair and then alters the molecular structure of the natural hide so that it becomes more durable and less likely to decompose, as skin would normally do if unaltered. Once a hide is tanned, it becomes the material we call leather.
Automotive leather gets its color from the dying process. The funny thing is that the “dye” is actually a special kind of flexible paint that is sprayed onto the tanned cowhide. In fact, first the desired color is applied, then a coat of clear paint is sprayed over that as a protective layer.
These paints contain UV inhibitors and other ingredients that help to make them more durable.
This coating allows the vehicle designer to color the leather seat upholstery to complement the color scheme of the vehicle interior. In addition, the coating performs the more important benefit of protecting the leather from wear and tear.
The quality grade of the leather used in an automobile may vary by manufacturer. In general, the finer grades of leather will be used in more expensive vehicles. Composite leather is often used for the non-contact decorative inserts in door panels. Nonetheless, virtually all these leathers are coated in a fashion similar to that mentioned above.
Interestingly, the quality of the coating can also vary. I have personally witnessed the accidental removal of leather color coating from newer, supposedly high-end vehicles. Thus, it is important to remember that harsh scrubbing techniques are typically not recommended for any automotive leather.
The two most common methods currently used to clean leather are (a) manual techniques, using leather cleaner and a brush, and (b) steam.
In the case of manual techniques, a cleaner designed specifically for automotive leather is applied to the leather, then agitated with a soft hogs-hair or horse-hair brush, or one of many scuff pads that are safe to agitate leather. In the case of really old seats that have thick layers of grime, careful use of a melamine sponge will help, with the awareness that this will take off some of the original coating as a sacrifice to get the leather looking clean again. The remaining cleaner and dirty residue is wiped away with a clean towel.
Most technicians will use a microfiber towel that is color coded “for interior use only.”
A dry vapor steam machine can also be effective at cleaning leather. No chemicals are necessary when using steam, the heat from which loosens caked-on grime and dirt with minimal agitation and has the side benefit of disinfection. Just be careful to use the machine on a low setting, as the steam can also remove the original leather coating. Some technicians use a combination of steam and manual cleaning.
It is important to remember to use cleaning techniques that minimize the possibility of removing that protective coating, including the use of a mild, pH-neutral (pH of 6-9) cleaner as well as soft scrubbing devices. Many “all-purpose” cleaners are far too strong to use on automotive leather, even if diluted.
Once clean, the leather needs to be properly conditioned. Use only leather conditioners designed for use on automotive leather. Using saddle products or those for furniture leather may actually damage the coatings typically used for automotive leather. Apply your automotive leather conditioner liberally, allow it to soak in, then buff off the excess with a clean utility towel. I recommend using a conditioner with ultraviolet blockers, as the sun is the one element that will cause the most damage to leather, next to normal use.
Dressing designed for use on rubber or vinyl is not recommended on automotive leather. This type of dressing can leave the leather feeling greasy, looking unnaturally glossy, and slippery for the passenger sitting in the seat. And some dressings, especially those with a solvent base, can actually damage the leather over time.
Appropriate leather dressing will not only make the leather look and feel nice, it can actually help to preserve the natural material. Although I mentioned that leather is protected with a coating of paint (“dye”), that layer of paint breaks down over time. In fact, there are microscopic cracks in new leather coating within six months of use. The appropriate conditioner will penetrate those cracks and lubricate the collagen that makes up the top layer of the leather that is just underneath the coating. The more lubricated this layer remains, the longer it will take for the leather to break down.
Speaking of which, normal wear-and-tear of leather is unavoidable (unless you never sit on the seat). Indeed, those microscopic fissures described earlier will lead to scuffing off of the dye, which leads to cracks. It can take months or years for this process to occur, depending on the amount of use the seat gets and the quality of the original upholstery.
Most of us have encountered, when cleaning a driver’s seat, the dark patches that occur upon moistening the seat with leather cleaner. This is usually exposed bare leather in a spot where the coating has worn off. Sometimes these patches look like dirt, prompting the customer to ask if the area can be cleaned. Unfortunately, standard detailing techniques will not fix leather scuffing or cracks. These types of damage must be repaired by an interior surface repair technician.
Aniline leather is genuine leather that is dyed differently than most leathers used in automotive applications. There are very few specific vehicle models that use aniline leather. Unlike the color coat that most automotive leather receives, aniline leather is dyed in a drum with a clear protective coating that allows the natural grain and imperfections of the animal hide to show through.
It is recommended that the pro detailer follow the manufacturer’s recommendations for cleaning and protecting aniline seats, as using the wrong chemical or agitation device can permanently damage the appearance. Some leather experts actually recommend doing nothing to clean or condition aniline leather, as its staining and wear and tear over time add character to the appearance.
Then there are the upholsteries that look, feel, or are labeled to be very similar to natural leather. “Leatherette” is an upholstery that was used for many years in Mercedes vehicles. It is actually a vinyl product. “Pleather” is a proprietary example of a newer type of vinyl that is very close to the look and feel of leather. There are a number of other imitation leathers, which really look like natural leather and have a soft, supple flexibility that most leathers do not. Other common names for imitation leather are: faux leather, vegan leather, and PU (polyurethane) leather.
Cleaning and conditioning imitation leather is as simple as using the same safe cleaning techniques that you use for leather seats. Using vinyl dressing on imitation leather seams like a logical idea, but it can make the seats slippery and greasy for the seated customer. Using automotive leather conditioner is a great alternative, or simply don’t use the vinyl dressing on the contact areas of the seat.
Suede or Nubuck
A newer but still rare seat upholstery choice is suede. True suede is actually the rough side of leather, finished to have a velvet-like nap. A popular form of suede is “nubuck,” which is a finer grade of suede. The difference between suede and nubuck is one of appearance and feel, but they are both natural products from cowhide and are cared for in the same manner.
The care of suede or nubuck is generally limited to dry brushing or careful use of a steam machine. You should have a suede brush on hand (available from a shoe store or furniture store), but, in a pinch, a clean, stiff-bristled nylon brush or even a wire brush can work, if used carefully.
Then, there is a category of upholstery that is essentially fake suede, sometimes called microsuede because it has a suede look and feel but is actually made out of microfiber. This includes name brands like Alcantara and Ultrasuede.
Seats upholstered in vinyl can be easily cleaned using a mild solution of your favorite multi-purpose cleaner, a soft scrub brush or scuff pad, and a microfiber towel. Spray the cleaner directly onto the seat, scrub with the brush, and wipe away the remaining cleaner residue and dirt. We generally use vinyl and plastic dressing on most surfaces inside the car. Vinyl seats, however, should not be dressed using standard dressing, which can leave the seats slippery. Instead, dress vinyl seats using automotive leather conditioner.
Cloth seats can be cleaned using a dry vapor steam machine or hot water extractor. A hot water extractor will provide better results than cleaning by hand or with a wet-dry vacuum. However, even the most powerful extractor tends to leave the seats quite damp. A dry vapor steam machine, on the other hand, will not do this since it uses much less water than the extractor, and the steam machine only cleans the surface without soaking the foam underneath the surface.
A dry vapor steam machine will not leave seats damp.
Whether using steam or extractor, the cleaning process is similar: Spray the seats lightly with cleaning solution designed for cloth, scrub with a stiff-bristled scrub brush, and “rinse” using the machine. Tougher stains can usually be treated using the same favorite spot removers that you like to use on carpeting.
A couple of notes: When using steam, it is often not necessary to use any chemicals for cleaning cloth seats. If using an extractor, place an air mover on the seat to speed up the drying time. Once the seats are dry, you can apply liquid repellent “cloth guard” as an extra service (with an extra charge).
Cleaning Leather Versus Vinyl
As mentioned earlier, an increasingly large majority of modern vehicles have seats that are upholstered in leather, or are at least “leather trimmed.” Sometimes it can be difficult to determine whether or not the material is leather or vinyl, as vinyl grain-stamping techniques can closely imitate leather grain and feel. (Take comfort, for I, the supposed “expert,” have been fooled more than once.)
If you are not sure, simply treat the upholstery as if it were leather. The cleaners and conditioners recommended for use on leather are also safe on vinyl. However, the cleaners used for vinyl are not necessarily safe for leather.
The professional detailing technician must be an expert at cleaning and protecting all of the surfaces on a vehicle. This includes leather, which is an especially sensitive material that requires specific techniques and care. Learning such techniques will help the technician to provide superior service and results, adding to the value provided to the customer through preservation of the automotive leather.
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 firstname.lastname@example.org.