Abstract: This invention relates to a method in the operation of magnetic separators comprising a plurality of canisters or like devices (4) containing magnetizable induction poles (41) arranged to pass through a magnetic field (1). While the canisters (4) are located in the magnetic field (1), a particle suspension is supplied (5) to the canisters, in which magnetizable particles are attracted to the induction poles (41). Rinsing fluid (6) may optionally be supplied to the canisters while the canisters are still located within the magnetic field (1), thereby to remove non-magnetic particles through discharge means (7a, 7b) for fluid and non-magnetic material. Outside the magnetic field flushing fluid is supplied in a flushing station (8, 56), this flushing fluid removing magnetic material through discharge means (8, 57) for magnetic material. The canisters (4) are provided with flexible sealing lips (36) as disclosed in U.S. Pat. No.