Steve, I have the worst-case scenario you describe. A steel door (Pease)was installed incorrectly(not by me!) in a hectic stage of our farmhouse gutting project. There is no hope for resquaring as it has been sided around on the outside and plastered around on the inside. The door opens and closes fine (which is part of the reason it did not get detected sooner), but there is a gap showing daylight at the top on the non-hinged side. Is there anything non-destructive that can be done to help seal this gap? I was thinking something along the line of a weatherstripping application or something?? I don't have too much room to play with the bottom hinge, but I really liked the golf tee idea, as I have been in that situation before!