A method for processing waste chewing gum to form granules, wherein the granules have a D50 diameter is provided, the method comprising the step of granulating the waste chewing gum in a granulator, the granulator having a screen comprising a plurality of rectangular holes through which the granulated material passes, wherein the holes have a side of length x; and where the following relationship applies: D50=A x2+B x+C  [Formula I] in which A, B and C are constants.