The most common use for anionic surfactants is as spreading, wetting, emulsifying, foaming, and dispersing agents. It is found in many commercial and industrial carpets cleaning solutions precisely because of these qualities. They work well at removing stains like clay, dirt, and oil. They produce more foam on average than other types of surfactants. Anionic surfactant groups include alcohol sulfates, sulfonic acid salts, phosphoric acid esters, carboxylic acid salts, and alkylbenzene sulfonates. Common anionic surfactants that can be found on the ingredients list in carpet cleaning products include ammonium, magnesium, sodium, and sulfate. A common trait among anionic surfactants is possessing a negative charge on the hydrophilic end that charges surfactant molecules to interact with soil particles and carpet fibers. Products containing anionic surfactants tend to leave a powdery or flaky residue once dry. That combined with their foam-producing quality makes them a popular component of certain carpet applications.