Cleaning substances are often used to remove dirt, grease, and other contaminants from surfaces. LYE, a 3-letter word, is a strong alkaline substance that is often used for cleaning. It is also known as sodium hydroxide or caustic soda. SOAP, a 4-letter word, is a surfactant that is commonly used for cleaning. It is made from fats or oils combined with an alkali, such as LYE, and can be used to remove dirt, grease, and other contaminants from surfaces.