English: If plastic flaps are at the outside end of the duct, one maybe able to flex, bend, and temporarily remove the plastic flaps, clean the inside surface of the flaps, clean the last foot or so of the duct, and reattach the plastic flaps. The plastic flaps keep insects and birds out of the dryer vent pipe. During cold weather, the warm wet air condenses on the plastic flaps, and minor trace amounts of lint sticks to the wet inside part of the plastic flaps at the outside of the building.