משנה על במדבר 18:26

If food that was tithe had been rendered susceptible to impurity by a liquid, and a tevul yom or one with unwashed hands touched it, terumah of tithe may still be removed from it in purity, since it only has third degree uncleanness, and third degree uncleanness counts as clean in hullin.

A flagon was a tevul yom and they filled it from a cask containing tithes from which terumah had not yet been taken: If one said, let this be terumah of tithe after nightfall, it becomes terumah of tithe. But if he said: let this be the food for the eruv, he has said nothing. If the cask was broken, the contents of the flagon still remain tithe from which terumah had not yet been taken. If the flagon was broken, then what is in the cask still remains tithe from which terumah had not yet been taken.