The term 'CLEAN WITH HARD RUBBING' can be broken down into three crossword solutions: SCOUR (5 letters), SCRUB (5 letters), and SCOURS (6 letters). Scouring is the process of cleaning a surface with hard rubbing, usually using an abrasive material such as steel wool. Scrubbing is similar to scouring, but it is done with a stiff brush or cloth. SCOURS is a more intense form of scouring, which involves the use of a wire brush or other abrasive material to remove dirt and grime from a surface.