My customers always bring back their cartons and I have friends save them from their store bought eggs ::shudder::. Every once in a while they'll bring me a cardboard one. I just smile, say thank you, and then throw it out. I want to be like "um how am I supposed to wash this to reuse it?!" But I'd rather they just give me what they have. If its in bad condition I chuck it. I have a 3 foot high stack that I doubt I'll ever go through with me measly 8 birds.