Here are some methods I've heard of for opening them:

  Cold - Put the stack in a grocer's freezer, and find an area on the
         freezer floor that's not properly leveled.  Place stack so
         it spans a valley in the floor.  Once it's good and cold,
         jump on it!  It'll bust open.

  Heat - Build a metal box that'll connect to a microwave oven with
         the front door removed.  The box will be long enough to hold
         the stack, and must somehow defeat the interlock.  It'll act
         as a waveguide.  Cook until done, -er-, -ah-, melted.

  Wham - Work at it with hammer and chisel as Reblitz recommends for
         general undoing of glue joints you cannot heat.

I've not tried any of these.  I sent mine to some guy in Missouri, and
was not really pleased with the result.  It's not tight, and I had to
do a lot of fiddling to get things working right.

 [ Editor's Note:  It would seem this and the next message contain
 [ some -well, umm- humor.  Those not sure which of the suggestions are
 [ serious should skip the suggested experiments...
 [ Jody