And don't listen to the nonsense you'll hear shortly about playing a hairdryer over them before using them next year to 'revive' the foundation. It's nonsense.
Had a stack of over a dozen boxes (deeps and shallow) left outside all winter with just a spare roof over them, bees were in there and drawing them out like a shot this spring. Even had stored foundation years old and the bees have treated it the same as 'fresh'