The third chapter is devoted to the commercial dishwasher itself. First, this chapter covers the basics of commercial, machine dishwashing, such as the individual steps involved in dishwashing and how the factors of Sinner's circle affect the dishwashing result. The individual types of warewashers are then listed and described. This is followed by the operation of a dishwashing machine in terms of the resources used, maintenance and hygiene requirements. The materials used in a dishwasher are also listed and information is provided on their use and properties. Here, the material compatibility of the materials plays an essential role. The chapter concludes with a table of 26 materials that are resistant or non-resistant in commercial dishwashers.