This part of ISO 16232 describes the principles of extraction of contaminants from a component either by immersion in an ultrasonic bath or by applying ultrasonic vibrations directly via sonotrodes. It is preferably applied to small and medium sized components of various geometry of which both internal and/or external surfaces have to be examined (e.g. joint seals, gears, etc). It is also applicable to small parts to be analysed in batches. This method can be used on its own or in association with other methods of extraction described in the ISO 16232 series.