You will have to remove it by "lifting" it from the bottom all the way along the molding. You can NOT simply start at one end, and "peel" the thing off. If you do, you end up with a piece of crap like the one I was sold a couple of months ago by a member here for $40. I was told it had "a slight wave in it", but this thing looked like a Hoop Skirt.
I actually used a can opener to get the moldings off my old 1960 Belair. Like the kind we used to open oil cans with, but a screwdriver will work just as well.
Just take your time.
Good Luck!!
George