We buy them a crapload of toys, so they have something they're allowed to chew on/burrrow in/throw around without being destructive. Jude likes them okay, but most of the time, Hef and Holly would just push them out of the way until they chewed on their house enough to get our attention, so we'd give them a snack. It drove me crazy for a bit. Those fatties don't even want to play and have fun, they just want food.
I came up with the idea to "lace" their toys in grape juice. They love grapes! It's like candy, maybe even crack to them. So, we started rubbing down their toys with grape juice. It worked! They gnaw on their toys, trying to get the grape flavor! The cage was saved!
Except, now I think they're learning to just lick the juice off... ::sigh:: And they chew their cage to remind us to juice up their chew toys again.
Their hamburger chew toy, a stick ball thing, and some wooden blocks that I covered in juice.