Detergents work by attaching to soil molecules. All detergents, even properly diluted, leave a residue on carpet. This residue does what it was designed to do, attach to soil as it comes in contact with it. Once removed with Split! Carpet & Upholstery Cleaner, carpets stay clean more than four times as long! The same amount of soil enters the environment, but it finds nothing to stick to, and is easily vacuumed away.