Ultrasonic cleaners have been used for medical, dental, and industrial cleaning applications since the mid 1900's. The cleaning action works by sending a high frequency sound vibration (usually around 40,000 kHz) through liquid. This vibration "cavitation bubbles" which penetrate uneven surfaces. These bubbles burst with such force that contaminents adhering to the bubble surfaces are dislodged. This same bubble bursting force breaks the cell walls of bacteria and fungus causing them to instantly die. The ultrasonic cleaning process does not provide complete sterilization (ie: for surgical use) but is more than sufficient for everyday cleaning without harsh chemicals.