One of the larger surface areas to clean on the interior of a vehicle is the carpeting. This includes carpeted floor mats, carpeting on the floor of the vehicle, and any other surface inside the car that is covered in carpeting-like material (e.g., the lower part of some door panels).
Some technicians, me included, like to take out the floor mats and clean them before beginning the rest of the interior detail process. By doing so, the mats have a chance to fully dry by the time the detail is complete. Mats can be dried either by placing them in the sun or using air movers.
In general, I suggest that the carpeting that is still attached to the inside of the car be cleaned after everything else inside the car is cleaned. We save the carpet for last so that we don’t have to worry about dripping on ― or stepping on ― the carpeting while cleaning the other surfaces.
The basic process of cleaning carpeting consists of three primary steps. First, we remove as much of the loose dirt and debris by brushing and vacuuming. Second, we attempt to loosen and emulsify the remaining soil, dirt, and stains in the carpeting. I use the word “emulsify” here to represent the suspension of soil, dirt, and stains in a cleaning solution. Third, we extract the emulsion in order to remove as much soil as possible.
The focus of this article is the post-vacuuming steps, although the importance of the vacuuming step cannot be stressed enough. Proper vacuuming can dramatically reduce the time and effort needed to clean the carpeting.
Some operators even like to “dry brush” the carpeting before vacuuming. That is, using a polisher with a brush attachment or a stiff-bristled hand brush to agitate the carpeting, thereby loosening sand, dust, and dirt that might be embedded in the carpeting. Another way to accomplish dry-brushing and vacuuming at the same time is to use a vacuum attachment with stiff bristles that rough up the carpeting as you vacuum.
Carpet Cleaning Chemicals
The best approach to carpet cleaning leverages a three-part system. The first chemical should be an enzyme spot and stain remover that is sprayed directly into the carpet, then allowed to dwell for several minutes before applying agitation. The enzyme cleaner attacks stains.
The second chemical is a low or no-foam alkaline cleaner that will loosen and emulsify soil. After spraying the cleaner onto the carpet, agitate again. For agitation, there are several options. A simple stiff-bristled brush will go a long way to loosening soil and stains. To speed up the process, you can use a brush attachment inserted into a cordless drill. Similar-style brushes are available for use with random-orbit polishers as well.
Upon completing the extraction of the cleaning chemicals, a third product can be used — a peroxide based post-treatment that will sanitize and deodorize the carpet, as well as neutralize any leftover cleaning chemicals.
The Professional Way
The old way of carpet cleaning was the “bucket-and-brush” method that left a lot of water and soil in the carpet. Now, most professionals use hot water extraction or steam.
A typical hot water extractor unit consists of several components: a clean water “solution” tank and a recovery tank (for the dirty water); a pump to transfer the clean water from the unit to the specialized nozzle; a heater to heat that water; and a vacuum to suck away the emulsified dirt.
Why hot water? It will loosen the dirt from the carpeting much more effectively than cold water. Imagine trying to clean bacon fat out of a frypan with only cold water. Plus, the carpeting will dry faster if hot water is used.
A hot water extractor, as its name implies, heats the water used to rinse the carpet. A good extractor will be able to deliver water at a temperature ranging from 180-220 degrees Fahrenheit. Most modern extractors use an in-line heater that runs the water through a series of coils, thus heating the water as it is used. A good extractor will also have a powerful vacuum system designed to remove as much moisture from the carpeting as possible.
A unique aspect of a hot water extractor is the design of the extractor nozzle, which incorporates a way to inject the carpeting with water or solution with a way to extract the emulsion. The spray nozzle, activated by a trigger incorporated into the unit, sprays a wide fan of heated water onto the carpeting. The vacuum nozzle is specially designed to create maximum suction with a wide but thin opening.
The spray nozzle is typically attached to the underside of the vacuum nozzle such that, as the technician pulls the extractor head across the carpeting, the water that is sprayed onto the carpeting is almost immediately picked up by the vacuum. In theory, the soil in the carpeting is emulsified with hot water and removed all in one step. This is basically “rinsing” the carpet.
The instructions that come with most units suggest using carpet cleaning solution in the solution tank. Nonetheless, I recommend not using any cleaner in the solution tank. I recommend using only clean water. Instead, we will spray the cleaning chemicals directly into the carpeting, scrub with a stiff brush, and then use the extractor to rinse the carpeting. Essentially, the extractor becomes a device by which you can rinse the carpeting with hot water. By using this process, you will leave very little cleaning solution behind.
In fact, the only thing I ever put into the solution tank other than water is a very small amount (perhaps one ounce per gallon) of an odor-neutralizing chemical. This becomes part of the rinse water, infusing the carpeting with a bit of odor-killing chemical that will help to neutralize any remaining odors.
Even the best, most powerful extractor will not be able to pull all the soil and moisture from the bottom of the carpeting. Thus, you may experience a phenomenon called “wicking,” which is what happens when the fibers of the carpet still have some moisture, and any leftover soil at the base of the carpet will “wick” or migrate up the fibers. To help prevent this, vigorously wipe the carpet with a clean, dry utility towel immediately after rinsing with the extractor. If the wicking appears later, use a clean utility towel dampened with just water and gently wipe the area, which should remove any leftover soil.
Extractors are available in a wide variety of sizes and models. Generally, a mobile operation will want to stick with a smaller unit (e.g., 3 gallon), whereas a high-volume shop may want a larger unit that has a large tank capacity (e.g., 5 gallon or larger), reducing the number of times per day that the tanks have to be filled or emptied. Large production facilities find that centralized extraction systems provide the most efficient operation.
Extractor maintenance is rather simple but very important. Do not leave water in the solution tank. Use the vacuum hose to suck out leftover water from the solution tank. This will keep the solution tank from getting moldy and rinse the hose of leftover dirty water. Empty the recovery tank every day and spray odor neutralizer into it to prevent odors. Leave the lid off the recovery tank so it can dry.
Extraction Versus Steam
Another effective way to clean carpeting is by using dry vapor steam instead of an extractor. The preparation of the carpet is the same, but the final “rinsing” is performed with steam vapor versus hot water. The advantage is that carpets have far less residual moisture.
Most technicians find the steam machine easier to use than heavy extractor equipment. Steam is also more effective on stubborn stains because true steam is about 325 degrees Fahrenheit, versus around 200 for hot water.
If steam has one disadvantage, it is that it does not necessarily provide deep carpet cleaning; instead, it focuses mostly on the surface fibers. Steam is great for cleaning lightly soiled carpeting without soaking the carpets; that’s why I am such a strong proponent of using steam for “express” detailing.
Many technicians find it best to have both a steam unit and an extractor and interchange their use depending on the severity of the job at hand. I’ve also used both machines on the same job — using the steam to loosen stubborn stains and the extractor to rinse them out.
Dry Those Carpets
Once the carpets have been adequately cleaned, they must be dried. Of course, mats can be placed in the sun, but how do you quickly dry the carpets inside the car? This requires air movers. These devices, borrowed from the carpet cleaning industry, can blow up to 2,000 cubic feet per minute of air. Some are even heated.
Another way to dry the carpets inside the car is to turn on the car and use its own climate control system. Turn on the fan to its highest setting, direct the airflow to the floor vents, turn the temperature control to the hottest setting, and turn on the air conditioner. Why the air conditioner? It removes moisture from the air. So, you end up with a one-two punch of heat and dehumidification at the same time.
Summary
Carpet cleaning is an important part of interior vehicle detailing. It should be preceded by thorough vacuuming, followed by cleaning with a hot-water extractor for deep cleaning, or a dry vapor steam machine for lighter surface cleaning.
Prentice St. Clair, CD-SV/RIT, has been serving the automotive reconditioning industry since 1999 with impassioned consulting and training and the goal of increasing the profitability of the automotive detailing and reconditioning industry. He is proud to have been inducted into the International Detailing Association’s Hall of Fame. Prentice welcomes inquiries that lead to the opportunity to help readers achieve excellent results. He can be reached via call or text at (619) 701-1100 or e-mail at prentice@detailingprogress.com.