The term 'thoroughly clean' can be summarized by the crossword solution 'SCOUR'. Scouring is a cleaning technique that involves using an abrasive material to remove dirt, grime, and other substances from surfaces. It is often used on hard surfaces such as countertops, floors, and walls. Scouring is also used to clean cookware, such as pots and pans. The abrasive material used for scouring can range from steel wool to a special type of sandpaper. Scouring is an effective way to thoroughly clean surfaces and objects.