The jar was packed to survive being dropped from a plane. As I watched the cats explore the box and wrapping material, I finally had an inkling of why Toffee smashed my jar: to get a second one.
Toffee is cleverly hidden.
The cats played through the night and we awoke to paper all over the living room and kitchen. I gather it up occasionally when walking gets tricky, but I don't mind a little mess if the cats are happy. Even Wendy snuck up on Toffee and jumped him while he was buried in paper, scaring the heck out of him. Good girl.