This document discusses substrate cleaning in a laboratory. It lists common substrates like silicon wafers, quartz, glass, and ITO coated glass. Sources of impurities are oils, grease, dust. Cleaning methods include wet cleaning using acids or solvents and dry cleaning using heating or plasma. The sacred cleaning protocol involves multiple steps of detergent cleaning, solvent boiling, acid dipping, and ensuring the substrate is immediately used after cleaning. Important factors are minimizing exposure time and keeping accessories clean. Specific dos and don'ts of cleaning are provided. Costs of substrates and importance of responsible use are noted.