How do i open a jazz pickup

[Iome]

I've got two Schaller Jazz Humbuckers i'd like to put together in one big block humbucker, but the bridge P.U. has some foam between the two wirings makin' it larger than the neck P.U. Does anybody know how to open the plastic covers in a safe way? Do i have to make a shielding between the magnets when i put the P.U's together?

Cheers