Adhesion and removal of dirt in the detergent process is interpreted from the examination of interfacial phenomena. The energetic measure of the adhesion and removal reaction is estimated by the work of adhesion (Wa) of each system using the dispersion and polar force components of polymers and oily dirt. Soilability and washability of oily dirt are estimated from the values of Wa. The correlation between Wa and washability is confirmed through experiments. The limitations and applicability of this surface energy analysis to the detergency system are then discussed. -- AATA