Keilim 2:3-4
Keilim 2:3
The following earthenware vessels are not susceptible to ritual impurity: a flat slab with no rim, an open coal shovel, a griddle for roasting, pipes – even if they’re curved and have receptacles, the raised cover of a bread basket, a jug that was converted to cover grapes, a barrel used by swimmers, a jug on the side of a barrel at the bottom (as handles), a bed, a chair, a bench, a table, a boat and a lamp. The general rule is that any earthenware vessel that doesn’t have interior airspace is not susceptible to ritual impurity on its outside.
Keilim 2:4
A lantern with a receptacle for oil is susceptible to ritual impurity but one without such a receptacle is not. The slab on which a potter starts his work is not susceptible to ritual impurity but the one on which he finishes is. A homeowner’s funnel is not susceptible to ritual impurity but the one used by a peddler is because it is also used as a measure; this is the opinion of Rabbi Yehuda ben Beseira. Rabbi Akiva says that the reason a peddler’s funnel is susceptible to ritual impurity is because he turns it on its side for the customer to smell perfume samples (and so it’s a container).