You don't have to remove it to clean. With the cap off, run a wire, rod or punch through the hole, using larger diameter until the tube is clear. Replace the cap. If the cap is not usable, make one from tubing just larger than the vent. Pinch one end shut and crimp the other end around the body. Crimp should leave the sides open, leaving room for the air to vent.
If you feel the need to remove one pressed in, heat the axle housing with a torch. This should expand the housing and break the seal.
If you need a replacement, go to
www.McMaster.com/vents
