We saw these onion savers in the produce department at our neighborhood grocery last night, and we were intrigued. Apparently the saver is designed so that when your unused half (or 3/4) of an onion is sealed inside, the saver helps keep the onion fresh, moist, and airtight. Have you ever used one of these, and do you think it's useful?We don't usually have a lot of leftover onions; they go pretty quick in our style of cooking! But when we do we just store them in a small baggie in the fridge and use them up quickly. But if your style is to use a slice here and there for a weekend burger or salad, then this may be helpful, perhaps?
You can see a little more about these onions savers at their Amazon page: