Abstract: A molded plastic lid adapted to generally close off the upper open end of a container and adapted to enable separation of entrained particles from a stream of air for collection of the particles in the container. The lid is formed with circumferentially extending inlet and outlet chambers opening downwardly into the container and having inlet and outlet openings, respectively, for receiving and discharging the air stream. The inlet chamber is formed with an upper surface which slopes downwardly upon progressing from the inlet opening to cause the air entering the container to flow in a curved and downwardly inclined direction so as to establish a cyclonic action in the container for separation of the particles. The outlet chamber is formed with an upper surface which slopes upwardly upon progressing toward the outlet opening to cause the air exiting the container to flow in the same generally curved direction but at an upwardly inclined angle.