The requirements a component has to fulfill vary depending on the factory standard from overall particle mass (mg/component) to particle size distribution of performance-critical components. Differentiation is executed for hard and soft matter, metallic and non-metallic particles, fibers, filaments, shot, conducting and non-conducting particles.

Microscopy is performed in the field of technical cleanliness in most cases with the help of a light microscope enabling the determination of particle sizes and (in defined borders) differentiation of metallic and non-metallic particles as well as fibers and filaments.