Ritual defilement of utensils is a topic to which an entire tractate of Mishnayot – Masechet Keilim – is devoted. In a number of places the Torah teaches the laws of utensils that come into contact with dead creatures and become tameh (defiled). For example, in Sefer Vayikra (11:29-35) the Torah lists different types of animals that defile upon their death, and includes the kinds of utensils that can become defiled. Similarly, in Sefer Bamidbar (31:20-23) in the context of the booty captured by the Children of Israel in their war with the Midianites, we learn of different materials that will become tamehand must be purified for use. Generally speaking, there are seven types of utensils that fit this category: If they are made of metal, wood, animal skin, bone, cloth, sack or pottery. In addition, glass utensils can become tameh on a Rabbinic level.
The Gemara on today’s daf (=page) teaches that there are some types of utensils that do not become ritually defiled, neither on a Biblical nor on a Rabbinic level. These are klei avanim, klei gelalim and klei adamah, which retain their “earthiness” and are not considered to be full-fledged utensils that would render them important enough to become tameh.
Klei avanim are stone utensils. Klei adamah are utensils made from earth. Some explain that they are made from stones that have been sanded down, others suggest that they are earthenware that never was placed in a furnace to be finished. Klei gelalim may be made from a large stone that can only be moved by rolling; others suggest that these are made from animal excrement.
In this context the Gemara brings a question posed by Rami bar Hama – if an elephant swallows a kefifah Mitzrit – a basket woven from Egyptian reeds – and excretes it whole, is it considered klei gelalim to the extent that it would no longer be considered tameh? While the Gemara rejects this possibility, it does consider whether if the elephant ate the reeds themselves and then excretes them that they may be considered gelalim so that a basket made from them would be considered klei gelalim.