Keilim 10:1-2

Keilim 10:1

The following types of vessels protect their contents when they have a tight seal: those made of dung, stone, clay, earthenware, natron, fish bones or skin, sea animal bones or skin, and wooden vessels that are ritually clean. These protect whether they seal on their mouths, their sides, standing on their bottoms or tilted on their sides. If they were inverted so that their mouths were on the bottom, they protect anything that is under them down to the deepest depth, though Rabbi Eliezer declares it ritually unclean (not considering the ground to be a valid seal). The aforementioned vessels protect everything from impurity except for an earthenware vessel, which only protects food, drink and other earthenware vessels.

Keilim 10:2

The tight seal can be made with lime, gypsum, pitch, wax, clay, dung, cement, potter’s clay, or anything else that spreads. We can’t seal with tin or lead because it’s a covering but it’s not tight. We may likewise not make a tight seal from an oily fig cake or dough that was kneaded with fruit juice because these could be rendered unfit but if one did make a seal from one of these, it protects its contents from impurity.