The entire galvanized line in the picture (~2") will no longer be used. I need to remove as much as possible, as I'll be sistering the joists it goes through. The toilet it connects to will still be used, so I need to seal it. Can I just remove the line at the elbow (Since I can't unscrew the elbow) and put a pipe plug in the elbow? Is it that simple, or is there a standard/required method?