To sell it on ebay so someone don't go and buy a brand new item while yours is contributing to the atmosphere's carbon dioxide by being burnt a few days after you've disposed of it. Alternatively, continue using it until it's "worn out". If your aim is "ethical living" that is, that's how I'd interpret it. The item is already made, it's there, and can't really be disposed of without contributing to the world's already big garbage heaps. ... (Another story if you don't want to eat from it because you're afraid of chemicals in the plastic, but you could still use it for storing, say, screws or coins.)