This is a large topic of study. It refers to any productive extraction and includes juicing fruits and vegetables and wringing (desirable fluids) out of cloths, as the juice or water inside the fruit is considered 'desirable' for these purposes, while the pulp of the fruit would be the 'undesirable.' As such, squeezing ("S'ḥita") is forbidden unless certain rules are applied. The wringing of undesirable water out of cloths may come under scouring/laundering. This activity could be viewed as extraction, while sorting (see below) is more akin to purification.