Is there a piece of glass in it? If so, soak it in warm water then get some pliers,(Or nail clippers, as an alternative) And ply it out slowly. then (or if there was never glass in it) let it soak in...
No, not on the roses but on their pinesues.
So that nothing can eat them. It is a defense mechanism. If an animal bites into a rose, and gets a mouthful of thorns, they won't want to eat it anymore.