Abstract: A cleaning system for a combine including at least one sieve located in a housing of the combine such that a flow of air from a fan mechanism is directed upwardly therethrough. The sieve includes a plurality of louvers which are are arranged relative to each other to define a first series of clean grain passages therebetween. A majority of the louvers define a series of openings which define a second series of openings which allow clean grain to pass therethrough and facilitate an increased flow of air therethrough to enhance separation of unwanted residue from clean grain.