This paper addresses the state of the design art in Direct Access Storage Device cleaning technology throughout IBM. DASD design trends during the last ten years have forced the concept of extremely low head flying heights to be developed to their ultimate in Manufacturing Engineering. This has caused us to move onwards from class 10,000 down through class 100 towards class 10 in terms of cleanrooms and process design. Parts contamination levels have had to move in a commensurate manner in order to satisfy build criteria. Cleaning plant design has therefore been enhanced to highly complex levels in order to match these developments. The most basic form of cleaner was designed to remove grease, oil and crude manufacturing soils from metal parts and has established the fundamental parameters of cleaning plant design in the form of the Degreaser.