Each piece is cleaned by a powerful spray-wash jet, effectively scrubbing the exterior surfaces. This is usually followed by an immersion and agitation process that flushes out blind holes, hollow parts, tubes and the like, using an aqueous solution. A typical washer also rinses and dries, so parts are ready for use after exiting the machine. A washer may also include additional processing stages, such as ultrasonic cleaning, rinsing, rust proofing/inhibiting, phosphating, sealing, lubricating, coating, etcetera. Stainless steel rotary drum parts washers are considered the most frequently recommended because they have a longer life.

The washers yield a very thorough clean on not only metallic materials, but on all materials fed through it. It effectively removes oil and chips that may be present. Another benefit of the rotary washer is its automatic controls. It can be fed automatically from another machine, such as a stamping, screw, die-cast or grinding machine.

This allows for an increase in productivity and a reduction in labor costs, as fewer operators are required to run the machine. Furthermore, the automatic design means that the operator's physical output is much lower. The washer can be custom-designed to optimize speed of productivity, to allow for cleanliness requirements, etc. This equipment has a wide array of applications. It can most notably be used in the auto industry, but can be applied anywhere that delicate parts need cleaning on a large scale.