Wet shampoo carpet cleaning with rotary machines, followed by thorough wet vacuuming, was widespread until about the 1970s. Industry perception of shampoo cleaning then changed with the advent of hot-water extraction. Wet shampoo carpet cleaning residues can be foamy or sticky, and this cleaning often leaves dirt un-extracted. Since no rinse is performed, the powerful residue can continue to collect dirt after cleaning, leading to the misconception that carpet cleaning can lead to the carpet getting “dirtier faster” after the cleaning.
When wet-shampoo chemistry standards converted from oil soaps to synthetic detergents as a base, the shampoos dried to a powder, and loosened dirt would attach to the powder components, requiring vacuuming by the consumer the day after cleaning. Most carpet cleaning services do not use shampoo methods to clean either residential or commercial carpeting today.