If I were you, I would try to use them. But either keep an eye on them while you charge them, or use a LiPo safe bag. If you just watch them, watch that they don't puff during the charge. Your batteries may not hold a charge as long as they did when they were new, but should work fine. So, instead of a 15minute flight, you may only get 10-12 minutes, but that's still worth using instead of spending more money. Unless the voltage dropped too low during storage. But your charger will yell at you if the batteries are no longer any good. Well, depending on the charger.