I'm no expert at anything, but I have installed many a door w/s. Use one of those disposable small parts brushes(you know the kind, small tubing w/horsehair in one end, used to be popular for flux). I do about a foot at a time & use spring-type clothespins. When it is all glued down & "stuck", I remove the clothespins & shut the door. Black glue doesn't show as much, use nothing to clean fresh paint-it comes off as you found out.
