Beis Shammai say: He opens and pours into the vat, but Beis Hillel say: He opens and does not need to pour. When are these things said? In a place where it is the way [for containers] to be sold closed; but in a place where it is the way [for containers] to be sold open, the container does not go to chullin. But if he wants to be strict with himself to sell by measure, the container goes out to chullin. R' Shimon says: Even [if] one says to his friend: “I am selling you this barrel except for containers,” the container goes out to chullin.