When a person holds a contract that represents something of value, who owns the piece of paper upon which the contract is written?
That is the point of a question posed by Rav Yeiva Sava to Rav Nahman in reference to ha-mahazik shetarotav shel ger – someone who has legal documents of a convert in his possession (should a convert die with no children, since there are no heirs his possessions become hefker – ownerless – and can be claimed by anyone). When presented with this question, Rav Nahman asked (incredulously), “Ve-khi la-tzut al pi tzlohito hu tzarikh?! What would he use it for? To stop up a bottle?!” In response Rav Yeiva Sava replies, “La-tzur ve-la-tzur – people really do have this in mind, as well, when they take possession of a legal document.”
In the ancient world, which was, generally speaking, poorer in terms of physical resources than the modern world, any object, no matter how small or insignificant, was used to its fullest extent. The tzlohit – the bottle – discussed here was a utensil, usually made of clay, with a narrow neck and small opening used for storing liquids like wine or oil. Most clay vessels were made with matching covers from the same material that would be used to protect the integrity of whatever was stored inside. Tzlohiyot were an exception, and covers were not always made for them, so when they needed to be closed any available material suitable for that purpose was used.
In this context it is worth noting that the “paper” of those days – which was actually a type of papyrus – was much stronger than what we use today, which is why is could have been used to stop up a bottle and protect its contents. Nevertheless, this was certainly a minor use of the material and its value – even in those days – was minimal.