The purpose of screening is to separate contaminants such as shives in mechanical pulp,and stickies,plastics ,sand ,metal pieces,and flakes in recycled fiber. This method employs a screening device and the separation is based on size difference between fibers and contaminants. However,depending on their flexibility and /or geometry,not all of the contaminants that are larger in size than fiber can be captured by the screen.

Screening plates of various slit widths such as 0.10mm,0.15mm, 0.20mm,and 0.25mm have been used in separating contaminants.