The rotary shampoo carpet cleaning method is the oldest method currently used for carpet cleaning. It is still among the best carpet cleaning methods in use today, but it is used by very few carpet cleaners. The shampoo method received a great deal of negative publicity during the early years of carpet cleaning due to the ineffectiveness of chemicals. As described earlier, many of the early carpet cleaning chemicals were true soaps that left a residue on the fibers. These residues caused a rapid re-soiling problem. In addition, the early rotary shampoo machines did not have the benefit of extraction as many of these units have today. Today’s machines offer the advantages of improved chemicals, brushes that offer excellent agitation and extraction to remove embedded and suspended soils.