The following vessels protect their contents when they have a tightly fitting cover: those made of cattle dung, of stone, of clay, of earthenware, of sodium carbonate,⁠a of the bones of a fish or of its skin, or of the bones of any animal of the sea or of its skin, and wooden vessels that are always clean. They protect whether the covers close their mouths or their sides, whether they stand on their bottoms or lean on their sides. If they were turned over with their mouths downwards they afford protection to all that is beneath them to the nethermost deep. Rabbi Eliezer declares this unclean. These protect everything, except that an earthen vessel protects only foods, liquids and earthen vessels. How may it be tightly covered? With lime or gypsum, pitch or wax, mud or excrement, crude clay or potter's clay, or any substance that is used for plastering. One may not make a tightly fitting cover with tin or with lead because though it is a covering, it is not tightly fitting. One may not make a tightly fitting cover with swollen fig-cakes or with dough that was kneaded with fruit juice, since it might cause it to become unfit. If he did make a tightly fitting cover [from such material] it protects. A stopper of a jar that is loose but does not fall out: Rabbi Judah says: it protects. But the sages say: it does not protect. If its finger-hold was sunk within the jar and a sheretz was in it, the jar becomes unclean. If the sheretz was in the jar, any food in it, become unclean. If a ball or coil of reed grass was placed over the mouth of a jar, and only its sides were plastered, it does not protect unless it was also plastered above or below. The same is true with regard to a patch of cloth. If it was of paper or leather and bound with a cord, if he plastered it from the sides, it protects. If [the outer layer] a jar had been peeled off but its pitch [lining] remained intact, And similarly if pots of fish brine were sealed up with gypsum at a level with the brim: Rabbi Judah says: they do not protect. But the sages say: they do protect. If a jar had a hole in it and wine lees stopped it up, they protect it. If one stopped it up with a vine shoot [it does not protect] until he plasters it at the sides. If there were two vine shoots, [it does not protect] unless he plastered it at the sides and also between the one shoot and the other. If a board was placed over the mouth of an oven, it protects if he plastered it at the sides. If there were two boards [it does not protect] unless he plastered at the sides and also between the one board and the other. If they were fastened together with pegs or with bamboo joints there is no need for them to be plastered in the middle. An old oven was within a new one and netting was over the mouth of the old [new] one: If [it was placed such that if] the old one were to be removed the netting would drop, all [the contents of both ovens] are unclean; But if it would not drop, all are clean. A new oven was within an old one and netting was over the mouth of the old one if there was not a handbreadth of space between the new oven and the netting, all the contents of the new one are clean. If [earthenware] pans were placed one within the other and their rims were on the same level, and there was a sheretz in the upper one or in the lower one, that pan alone becomes unclean but all the others remain clean. If [they were perforated] to the extent of admitting a liquid, and the sheretz was in the uppermost one, all become unclean. If in the lowest one, that one is unclean while the others remain clean. If the sheretz was in the uppermost one and the lowest projected above it, both are unclean. If the sheretz was in the uppermost one and the lowest projected above it, any one that contained dripping liquid becomes unclean.