Carpet Cleaning - A Hot-Water Extractor Is Essential
By Prentice St. Clair
One of the larger surface areas to clean on the interior of a vehicle is the carpeting. Now, when I say “carpeting,” I am referring to carpeted floor mats, the 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, myself 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, however, I suggest that the carpeting that is still attached to the inside of the car can 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.
DON’T SKIP THE VACUUM
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 brush to agitate the carpeting, thereby loosening sand, dust, and dirt that might be embedded in the carpeting. Another way to accomplish the dry-brushing and vacuuming at the same time is to use a vacuum attachment that has stiff bristles that rough up the carpeting as you vacuum.
THE OLD WAY
The old-style method of carpet cleaning is to use a bucket of soapy water, a stiff brush, and a wet-dry vacuum. The technician would repeatedly dip the brush into the bucket and scrub the carpeting. Then, the technician would use the wet-dry vacuum in an attempt to suck out the emulsified soil and excess soapy water.
There are several problems with this methodology. First, the carpeting needs to be virtually soaked in order to adequately emulsify the soil. Some of this water will seep deep down into the nap of the carpet and even into the padding below. Even the most powerful vacuum cannot suck out all of this water. So the carpeting is left moist. Additionally, the attachments that come with the typical wet-dry vacuum are not designed for effective removal of water from carpeting.
A second problem with the bucket-and-brush methodology is that the carpeting is not actually rinsed, so some of the emulsion of dirt and soap is left behind. The result is that the carpet is not as clean as it could be, and the remaining soap tends to attract dirt, so the carpet will become re-soiled sooner than it should.
THE PROFESSIONAL WAY
I would guess that there are very few professional detailing technicians who are not using a hot-water extractor to clean carpeting. This device combines all of the essential elements needed to do an effective job.
A typical hot-water extractor unit consists of several components, including two tanks, 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. And the carpeting will dry faster if hot water is used.
A hot-water extractor, as its name implies, heats the water that will be used to rinse the carpet. A good extractor will be able to deliver water at a temperature ranging from 180 to 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 the maximum suction capability by use of a long, thin opening.
The spray nozzle is typically attached to the underside of the vacuum nozzle so that, as the technician pulls the extractor head across the carpeting, the water that is sprayed into 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 talk about using carpet-cleaning solution in the solution tank. Nonetheless, I recommend not using any cleaner in the solution tank. Instead, use only clean water. Spray the carpeting with a well-diluted solution of your carpet-cleaning chemical, 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, about the only thing I ever put into the solution tank other than water is a very small amount (perhaps one ounce per gallon) of odor-neutralizing chemical. This then becomes part of the rinse water, infusing the carpeting with a bit of odor-killing chemical that will help to neutralize any odors that might remain.
Use only carpet cleaner that is specifically designed for use with an extractor. This chemical will be low-suds so that the recovery tank does not become choked with foam.
Even the best, most powerful extractor will not be able to pull all of 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” up the fiber to the top. To help prevent this from happening, 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 in water only 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, whereas a high-volume shop may want a larger unit that has a large tank capacity, reducing the number of times per day that the tanks have to be filled or emptied. Large production facilities find centralized extraction systems provide the most efficient operation.
Extractor maintenance is rather simple. 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.
HOT-WATER 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 using steam vapor versus hot water. The advantage of this is that the carpets have far less residual moisture. Most technicians find the steam machine to be easier to use than the heavy extractor equipment. Steam is also more effective on stubborn stains because true steam has a temperature of about 300 degrees Fahrenheit, versus around 200 for hot water.
If steam has one disadvantage, it is that it does not necessarily provide deep carpet cleaning, but 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.
GET THOSE CARPETS DRY
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 the use of air movers. These devices, borrowed from the carpet cleaning industry, can blow up to 2,000 cubic feet of air per minute. Some are even heated.
Another way to dry the carpets on the inside of 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.
Carpet cleaning is an important part of an interior vehicle detail. It should be preceded by thorough vacuuming, followed by cleaning with a hot-water extractor for deep cleaning, or dry vapor steam machine for lighter surface cleaning.
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 email@example.com.