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:
• Onion savers in purple or tan, $3.39 at Amazon.com
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