Utah State University Report on Commercial Carpet Cleaning Methods

Method Application Advantages Disadvantages
Dry Foam Similar to liquid method, a detergent solution with minimum water is mechanically worked into carpet pile and loosened soil is removed by vacuum. Drying time is shortened due to small amount of water used. Low moisture content for reduced cleaning effectiveness on heavily soiled carpets.
Hand Absorption A detergent solution foam is worked into carpet pile by sponges. Loose soil is removed by absorption into clean sponges. Entire application is done by hand.   Expensive and time consuming.
Hot Water Extraction (Steam Cleaning) Hot water and detergent solution are sprayed onto carpet under pressure to flush out dirt. Solution is immediately extracted by a vacuum action of an extraction machine. Satisfactory soil removal, little distortion of carpet pile, one step operation. Heavily soiled areas and spots must be pretreated, as the short duration of the solution's contact with the carpet is insufficient for cleaning these areas. Extreme risk of overwetting. Duration of excessive moisture in carpet can cause carpet to shrink, jute backing to separate from carpet, and seams to separate. Also, premotes resoiling of carpet quickly.
Dry Powder An absorbent powder containing a dry cleaning fluid and other cleaning agents is applied to and worked into the carpet. After thorough drying (about one hour) the carpet is vacuumed to remove powder and attached soil. Because ther is a controlled amount of moisture involved, method may be used on delicate and non-colorfast carpets and rugs. This method is also good for lightly soiled carpets or between regular shampooings in high traffic areas such as on stairs and in doorways. Less effective than other methods on heavily soiled carpet and water base stains. Prolonged storage of cleaner may reduce cleaning effectiveness due to the evaporation of volatile ingredients. Complete removal of powder is difficult.
Rotary Buffer (Chemical Dry Cleaning) Concentrated cleaning solvents are diluted and applied with a sprayer and agitated with a cotton or yarn pad with a rotating floor machine to remove all oily and dry soils along with excess chemical. Best for thorough cleaning of medium to heavily soiled carpets and rugs. Leaves virtually no sticky residues, thus carpets stay cleaner longer. Dries quickly. Because of the superior cleaning effectiveness it is usually more expensive, but can be found at a reasonable price.
In Plant Rotary brushes are used to shampoo both sides of carpet or rug. Carpet is totally submerged to rinse out detergent. Any needed repairs can be made while carpet in in the plant For loose carpeting and area rugs that are easily removed from the home. Shrinkage, curling and fading may occur as the result of thorough wetting of the carpet backing.

For more information, contact the:

Utah State University Extension Services; OR
Betty L. Tisher, Director
Bissell Consumer Service Institute
P.O. Box 1888
Grand Rapids, MI 49501