Menachot 69: Ritually Impure Utensils

Today's daf discusses utensils that have come into contact with dead creatures and thus have become tamei, ritually impure.  Utensils made of metal, wood, animal skin, bone, cloth, sack or pottery can be purified after becoming tamei.  The rabbis have added glass utensils.  

The Gemara explains that three types of utensils do not become tamei according to Torah or the rabbis.  They are thought to maintain their connection to the earth:

• klei avanim are utensils made of stone
• klei agama are utensils made either of earth, sanded stone, or earthenware not fired
• klei gelalim are made of either stone that must be rolled to move or animal excrement

Rami bar Chama asks if an elephant swallowed a wicker basket (made of soft palm reeds that can be bent) and excreted it whole, would it be considered klei gelalim and thus not tamei?  This is rejected.  However, the rabbis agree that if the elephant swallows and excretes whole the reeds used to make a wicker basket, they could be used to construct a basket that is tahor, ritually pure.