removal belt the cleaning carriage has a cleaning lip which mechanically cleans the areas of the sliver opening devices especially endangered by contamination the cleaning carriage can be shifted as required relative to the impurity removal belt application_number US 23730299 A description referring now to the accompanying drawings and initially to fig1 several serially aligned open end spinning units 2 of an open end rotor spinning machine 1 are shown in front elevational view as is known in modem oe rotor spinning machines often far more than one hundred of these open end spinning units are arranged in alignment with each other along each side of the spinning machine these open end spinning units 2 which are known and described e g in german patent publication de 195 24 837 a1 comprise a suction loaded rotor housing 21 in which a spinning rotor 22 rotates at a high speed the rotor housing which is not shown in fig1 is open to the front and is closed during spinning operation by a swiveling cover element 3 swiveling cover 3 also comprises among other things a sliver opening device 4 sliver opening device 4 operates to separate a sliver 9 being fed to the spinning unit into spinnable individual fibers for such purpose the sliver opening device 4 comprises as is customary an opening cylinder 6 rotating in an opening cylinder housing 5 a delivery roller 7 and a sliver feed trough with a sliver compressor 8 facing to the front of the machine the opening cylinder housings 5.