Praise be to Allaah.
Firstly: those who are responsible for requesting samples for quality-control testing must ask for the amount that is usually sufficient for testing, and not ask for or accept more than what is needed.
Secondly: in cases where only some of the amount given is sufficient, whatever is left over must be handed back to its owner. His address should be written down on the sample, and an appointment should be made to give back whatever is left over from the tests. A name of a contact person and an address should also be obtained, so that the goods may be returned.
Thirdly: in the event that the owner of the goods or his representative does not keep the appointment, and there is the fear that the samples may go off, then they may be sold and the money raised should be given to Bayt al-maal al-Muslimeen (the treasury of the Islamic state). If they cannot be sold, they should be given away to the people who are usually taken care of by the bayt al-maal.