No box around here is safe from Joy. In fact, we have to keep a good eye on her when stuff is delievered because of the packing peanuts. We close the box by doing the old over/under with the top flaps but she'll still get a paw in there and fish out peanuts one by one and have them all over the house.
My cats are obsessed with boxes. I used to have all these lounges, and play centers that I got them lying around my house unused. But then I just gave them boxes. People are always asking me if I'm moving, "Nope those are for the cats" :lol:
Their favorite one is this giant television box that I cut a doorway into.
Just check for staples!