I thought the glue used in manufacturing was likely epoxy, but another poster reported that he'd actually removed the bracket by prying, and it appeared to be cyanoacrylate. If that's the case, you could soak the magnets for a few days in acetone to try to loosen them up—acetone dissolves cyanoacrylate, which is the main component of most superglue. (Unfortunately, the bond gap is usually so thin with cyanoacrylate that it may take quite a while to diffuse in. Gentle, continuous agitation may help.)
As for brackets on or off, have a look at the discussion in
this thread.