Elmer's doesn't work too well, but i've used Aileen's tacky combined with
chopsticks. There is a cheap gadget from the craft store that runs on
batteries, something like a wire cheese cutter.
Some people use an electric knife.
I glued together many layers of sheet insulation, cut it out, and made the
armature for a six foot long papier mache panther. The only problem --as the
mache dried it tended to sag, and miss panther looked pregnant. I had to do
an emergency C-section and wrap a few layers of Paris craft till she healed.
But she turned out pretty well--just slightly more plump than sleek.