Although I think that there cannot be too much onion (or garlic) in my food, most people do, and sometimes find themselves with a bit of leftover. There is no reason to throw out a half of a perfectly good onion. But it is not a good idea to keep uncovered cut onions in the refrigerator, they will quickly get stale and lose their flavor. And, more importantly, who wants their refrigerator, including all food in it, to smell like onion?
There are ways to keep onion fresh and avoid smelling up the fridge. Roll it up in a plastic wrap or into a plastic sandwich bag (sometimes it is necessary to do both to completely contain the odor.) But the most elegant and reliable solution will be this “Onion Saver“.Buy from Amazon