They are made of a cast 2mil vinyl and come with adhesive on the back. There are several ways when appling them to make sure they do not lift once on, but once they are on and start lifting there isn't much that can be done. 3M has a few things that might work and they make a car paint "primer" (for lack of a better word) that you wipe on the area before appling vehicle graphics that will make sure they stay on.
Good luck