This standard specifies the Measuring methods for the cleanliness of metal cutting machine tools, including visual inspection, feel method, weight method and particle counting method. It is suitable for testing the cleanliness of machine tools. Cleanliness refers to the degree of dirt (such as metal chips, sand, dust, etc.) present in the test object, and the cleanliness tolerance is the maximum allowable dirt content. The standard requires that the testing environment, personnel and utensils must be kept clean to ensure the accuracy of the measurement results. Relevant standards are quoted, such as paints and cleaning solvent oils, hydraulic transmission fluid contamination determination methods, etc., providing detailed guidance on cleanliness testing.