Ultrasonic cleaning uses cavitation bubbles induced by high-frequency pressure (sound) waves to agitate a liquid. The agitation produces high forces on contaminants adhering to substrates like metals, plastics, glass, rubber and ceramics. This action also penetrates blind holes, cracks and recesses. The intention is to thoroughly remove all traces of contamination tightly adhering to or embedded in solid surfaces. Water or solvents can be used, depending on the type of contamination and the part.