Aqueous ultrasonic cleaning cleans parts by emitting high-frequency sound waves in a water-based solution. The sound waves agitate the liquid and create cavitation bubbles that knock contaminants off the object at the molecular level.

It often broadly defined as a cleaning process that combines the chemical solvency of a water-based cleaning solution with some type of mechanical/thermal energy.  It has replaced and is increasingly opted over solvents on considerations of environmental regulations and safety and cost.