The deterging effect and wetting capacity of some widely used commercial surfactants and demulsifiers are examined and studied from the standpoint of the oilfield treatment of crude oil. The deterging effect of surfactants of various structures is shown to be selective in washing off disperse particles of mechanical paraffin, resin, and asphaltene impurities from the surface. New methods are proposed for determining the deterging effect of surfactacts in oil-bearing disperse systems. The mechanism of breakdown of the structure of disperse particles surrounded by a hydrocarbon adsorption layer under the action of detergents is described. The studies identified a number of surfactants that have an intrinsically pronounced deterging effect.