Abstract: A removable trash bag assembly for lawn mowers, wherein the bag is made of plastic and is hung from a frame attached to the mower. The bag is provided with hanging loops for easy mounting and removal with respect to the frame; and the mounting is arranged to flex the bag in tension to open slits provided in the side of the bag at its mouth due to the increasing weight of the trash as the bag progressively gets filled to exhaust the air when the primary vents in the mid-portion of the plastic are blocked. These slits also function to prevent bursting of a closed filled bag when it is dropped by providing vents at the top of the bag for any entrapped air. These slits are also functional to pass the folded open end portion of the bag therethrough to close the bag.