A top-side rotary brush is an assembly consisting of four to six narrow brushes with plastic bristles mounted 90 degrees apart from each other inside a triangle frame. The assembly rests on the separator screen’s surface, and the machine’s vibratory motion propels the assembly around the screen, allowing the brushes to clean the screen’s entire surface without requiring an additional drive motor. The rotary brush operates very quietly. The rotary brush is used to clean fibrous materials from the screen. As the assembly moves across the screen, the brushes ball up the mat that the fibrous material forms on the screen surface, exposing the mesh openings. The resulting fiber balls, too large to pass though the screen, are discharged from the separator. The rotary brush is a very effective top-side mesh cleaning system. The main disadvantages are that the brush bristles can fall into the material stream and contaminate it, and it is necessary to periodically clean the brushes. However, as with bottom-side cleaners, when the brushes wear out, you can simply replace them.