a. Dry soil: It is estimated that 85 percent of the soil in carpets and fabric upholstery is dry soil.
b. Oily soil: This represents the other 15 percent.
You can see that a very thorough vacuuming is critical to obtaining a clean carpet, yet many detailers simply “slop” the shampoo/water mix on the carpet without vacuuming at all, or doing only a cursory job of it assuming the shampoo will get the carpets clean. All this does is turn the dry soil into “mud” which is even harder to remove with just a shop vacuum.
Dry, clean, extract
The dry and oily soils mentioned are in addition to any severe stains or spots that may be on the carpets/upholstery and are specific in and of themselves. These stains and spots have to be removed by hand or with a vapor steamer before the shampooing process begins.
After any stains or spots are treated, the detailer may start with the following procedure for removing soil:
1. Thoroughly dry vacuum the carpets and upholstery. Some use an air blower to help raise the dirt and grit out of the fibers.
2. Approach each stain/spot with the appropriate stain/spot removal chemical. (Last month’s article, “The science of carpet and upholstery cleaning” explains the correct method.)
3. Pre-spray the carpets/upholstery with a foaming-type shampoo and let it dwell to emulsify the oily soil on the fibers. It is not necessary to saturate the carpet/upholstery with a great deal of moisture, as in most cases only 15 percent of the soil is oily.
4. Friction scrub with a hand brush or a rotary shampooer tool which will cause the shampoo to foam up and lift the oily soil off the fibers.
5. Use a heated soil extractor to rinse clean the fibers of the oily soil and shampoo residue. Do not rub the nozzle back and forth; this puts too much moisture into the fibers. Start away from you and pull the nozzle slowly toward you rinsing the fibers of all soil. It is advisable to have a view window in your extractor nozzle so that you can see when you have evacuated all the soil from the fibers.
6. Some detailers will use the extractor nozzle to “dry” vacuum after the extraction process to insure that they have gotten as much of the moisture out of the fibers as possible.
Many detailers exposed to these procedures balk at the time that it would take to clean carpets/upholstery in this fashion, opting for less throughout, but faster methods. However, a true professional will follow these aforementioned methods because these are methods advocated by the Carpet Cleaning Institute of America.
Choosing a soil extractor
Much of your success will depend upon the tools you have chosen for the job, including the type of extractor you use. Your detail shop must have a top quality heated soil extractor to get the job done properly.
The following are some guidelines to follow and factors to consider when choosing an extractor:
You have to choose the best extractor you can afford. With that said, you want to be certain to purchase a professional unit and not one of the low-cost residential units. They simply will not stand up to the rigors of daily use. Professional units can range in price from $650, $795, $1299, $1760 and up.
How many cars will you detail per day? You do not want to have to continually fill the tank. So purchase an extractor with a solution tank large enough to last all day or at least half a day without refilling. A mobile detailer who may only detail one or two cars at a single location can get by with a two or three gallon solution tank.
You can choose between a two-stage vacuum motor and a three-stage vacuum motor. The three-stage has the most suction. Do not be misled by dual-motor units. These are for residential cleaning where you may have to increase the length of the vacuum hose to reach up or down stairs without moving the extractor. The dual-motors maintain the suction with a longer hose.
You have a choice between a tank heater and an in-line heater. The in-line is the best because it gives instant heat. The tank heater has to heat up the solution, sometimes taking 10 to 15 minutes. The in-line heaters with higher watts are best: 1000, 2000, and 2400 watts.
The typical pressure of a pump is 100 psi, but you will find some at 150 psi.
Most vacuum hoses have the solution line tied to the outside of the hose. That is acceptable, but you can get a hide-a-hose, which puts the solution line inside the vacuum hose for easier use.
You want a stainless steel nozzle because they do not wear out or break like plastic. You also want a view window in the nozzle so you can see that you are extracting all the soil.
Take your time and shop around. Cleaning carpets and upholstery is as much a science as paint finishing and you simply cannot clean them without the proper tools and knowledge!
R.L. “Bud” Abraham is president of Detail Plus Car Appearance Systems, Portland, OR, and a nearly 40-year member of the car care industry. He is also the executive director of the International Detailing Association and a member of the Western Carwash Association Board of Directors. Abraham can be contacted at firstname.lastname@example.org.