Having never before seen how the trim is attached I'm wondering...what is the process exactly for removing it. Is the aforementioned tool used to "push" the trim out of the clips? Is that what a person does to remove it...dislodge the trim from the clips? How are the clips held in place?
The clip slides onto a pin that resembles a nail head that is welded onto the car body around the window frame. The trim then slides between the clip and the body and is held in place by the pressure of the clip. The clip has a ridge that locks the lip of the trim. The tool hooks the clip and pulls the clip away from the body and allows the trim lip to release and move up and away from the clip.
Maybe drawings from a shop manual will help show how it works. http://1bad6t.com/Maverick/repair/body_01.html#e