Crafting a pail takes three Metallic Ingots.
One Pail can be found in 18.8% of chests in Torture Chamber.
A filled pail can then be used to place it's contents in the empty hole next to the side of the object the player is currently looking at, or replacing the object looked at for some replaceable objects.
A bucket full of dairy cannot be emptied. Instead, it is a beverage.