1,728. On What a Get May Be Written

Hilchos Geirushin 4:2

One may write a get with gallnut juice on paper or on a hide but not on a parchment that was treated with gallnut juice because it will not be legible; such a get is invalid. This is true in all comparable cases. A get may be written on anything – even on a substance from which benefit is prohibited. A get may be written on something where erasures can’t be detected so long as it is delivered in front of witnesses.

Hilchos Geirushin 4:3

Pursuant to the previous halacha, if a get is written on a paper that has erasures, on a parchment that hasn’t been completely processed, on an earthenware shard, on leaves, on a servant’s arm or a cow’s horn, it is valid so long as the man gives the woman the servant, cow, paper or parchment in front of witnesses.