with the cotton at a predetermined and preselected temperature as the device moves over the cotton bales 63 when the device moves from left to right the plate like heating device 65 is heated and when the movement is in the opposite direction the plate like heating device 66 is heated the contact of the plate like heating devices 65 and 66 with the upper layer of the cotton bales 63 is such that it renders the honeydew particles or droplets brittle and hard advantageously both the plate like heating devices 65 and 66 are heated to the treatment surface temperature during passage of the flock or tuft detaching machine over the cotton bales 63 the illustrated flock or tuft detaching machine containing the plate like heating devices 65 and 66 may be used in addition to the aforedescribed heated roller devices or may be used to a large extent instead of the aforedescribed heated roller devices it should be clear that the inventive method can be effected before the blending of the cotton slivers to a single cotton sliver on a draw frame like for example the conventional draw frame 17 however the inventive method may also be brought into effect at any preceding stage of the processing of the cotton it should also be clear that the heating can.