A door that rubs or catches when opened and closed is inconvenience and can damage your door, flooring, and your door frame. Fix it in a few easy steps.
Step 1 - Find the Problem Area
Establish the rubbing area by closing the door on a sheet of carbon paper. An ink mark will reveal the mis-aligned portion of the door edge.
Step 2 - Sand
As you sand the mis-aligned area smooth, be sure to work the area beyond as well for a smooth surface.
Step 3 - Varnish
Once the rubbing area has been made smooth, seal the door edge with several coats of varnish or paint.
Courtesy of Dremel Tools