Ultrasound can be used in industry to detect defects in metals.
Materials can be tested for internal faults and cracks that could lead to the failure of a structure under certain conditions.
Ultrasound imaging provides a quick method of detection and perhaps prevents serious accidents.
Ultrasound can be used to clean jewellery.
The vibrations caused by the ultrasound shake apart the dirt, breaking it up.
The principle is the same as the opera singer's trick, where a glass may shatter if the singer makes a high-pitched sound near to the glass which causes it to vibrate with large amplitude.