Sentence:  Although there is no question but that the process of washing fabrics involves a number of phenomena which are related together in an extremely complicated way and that these phenomena and their interrelations are not well understood at the present , this section attempts to present briefly an up-to-date picture of the physical chemistry of <WSD>washing</WSD> either fabrics or hard surfaces . 
Meaning of the word marked with <WSD> tags:  the work of cleansing (usually with soap and water)