A detergent is a surfactant or a mixture of surfactants with cleansing properties when in dilute solutions. There are a large variety of detergents, a common family being the alkylbenzene sulfonates, which are soap-like compounds that are more soluble in hard water, because the polar sulfonate is less likely than the polar carboxylate to bind to calcium and other ions found in hard water.

Cleanliness is both the state of being clean and free from germs, dirt, trash, or waste, and the habit of achieving and maintaining that state. Cleanliness is often achieved through cleaning. Culturally, cleanliness is usually a good quality, as indicated by the aphorism: "Cleanliness is next to Godliness", and may be regarded as contributing to other ideals such as health and beauty.