Ultrasonic cleaning is a process that uses ultrasound (usually from 20 to 40 kHz) to agitate a fluid, with a cleaning effect. Ultrasonic cleaners come in a variety of sizes, from small desktop units with an internal volume of less than 0.5 litres (0.13 US gal), to large industrial units with volumes approaching 1,000 litres (260 US gal).

The principle of the ultrasonic cleaning machine is to convert the sound energy of the ultrasonic frequency source into mechanical vibration through the transducer. The vibration generated by the ultrasonic wave is transmitted to the cleaning liquid through the cleaning tank wall, so that the micro-bubbles in the liquid in the tank can keep vibrating under the action of the sound wave, destroying and separating the dirty adsorption on the surface of the object.

Depending on the object being cleaned, the process can be very rapid, completely cleaning a soiled item in minutes. In other instances cleaning can be slower, and exceed 30 minutes.

Ultrasonic cleaners are used to clean many different types of objects, including jewelry, scientific samples, lenses and other optical parts, watches, dental and surgical instruments, tools, coins, fountain pens, golf clubs, fishing reels, window blinds, firearm components, car fuel injectors, musical instruments, gramophone records, industrial machine parts, and electronic equipment. They are used in many jewelry workshops, watchmakers' establishments, electronic repair workshops, and scientific labs.