Onion cognoscenti offer a neat trick for prolonging freshness (especially with varieties that don’t usually keep so well, such as Vidalias): store them in pantyhose! Drop an onion into a pantyhose leg, and knot it off. Drop in another onion, knot, and repeat.
When you need to use an onion, just cut the hose off before the next knot. The rest stay protected! Hang your oniony pantyhose in a cool, ventilated area, and the onions will last for several months.
Bonus tip: to prevent weeping, hold a small piece of bread in your mouth as you chop (don’t chew!). Another trick is to keep a few onions at a time chilled in your crisper drawer (cold ones aren’t as gaseous).