To provide a method capable of selectively eliminating impurities in textile conveying air flow.

The textile air flow containing impurities is stacked on a stationary rotating suction drum mounted on the subsequent stage of the impurity inspecting section. These impurities and extremely small amount of textiles are blown off from the suction drum by compressed air which is supplied by a compressed air supplying pipe and blown out from the air blasting nozzle by the action of a magnetic valve when the impurities in the sludged textiles arrives to the apertural area, according to the rotation, in the region where the segment is mounted. This blow out timing is determined by the detection of impurities at the inspecting section.