Open or remove the door by taking it off its hinges so it doesn't interfere with your work. You may not need to remove the door if there's no weatherstripping attached to it or on the top and bottom of the entryway.
Locate the old weatherstripping, which should be attached to the side of the entrance where the door makes contact with the door jamb. There may also be weatherstripping attached to the top and bottom of the door.
Insert the prybar under the weatherstripping by gently tapping it with a hammer until it's securely in place.
Pull the prybar toward you, removing the old weatherstripping, working from the top of the entryway to the bottom. If necessary, work your way around the whole door. You can also use the claw end of the hammer, once you've begun the process.
Remove the weatherstripping from the top and bottom of the door using a screwdriver. This type of weatherstripping, known as a "sweep strip," is usually fastened to the door by several screws.
Clean up all debris, making sure there are no remnants of the old weatherstripping attached to the entryway.