The general principle (see Shbaat 75b) is that whatever is fit to be “put away” – that is, things that are generally saved for later use, indicating that they are valuable, are exactly the things which cannot be carried in public on Shabbat. These are plants, dyes, medicines, etc. But although the general principle has been explicated, there are many specific examples. Those continue on this page, including perfumes, scraps of metal – and, interestingly, the “moth-eaten [Torah] scrolls or their moth-eaten mantles” which are stored away to be “hidden.”
By looking at these specifics we see a lot of about the uses of certain materials at their time. Some are so specific, it is hard to imagine that rabbis intended their statements to be for all time.For example natron (natar) – a kind of soda ash which can be used for cleaning: The rabbis make it clear: “Alexandrian natron, but not natron of Antipatris.”
Obviously a difference which made a great deal of sense to them, but difficult for us to reconstruct.
More insight to the life of their times: it seems clear that locusts were kept as children’s pets!
But this “charm” charmed me.
The Mishnah speaks of a “Bird of the Vineyards” (tziporet karmayim) which cannot be carried out in any size, dead or alive. This seems to be not a bird at all, but a species of locust. And it has a use as a wisdom charm:
"Abaye observed: And it is found in a palm tree of [only] one covering, and it is prepared [as food] for [acquiring] wisdom; one eats half of its right [side] and half of its left, places it [the rest] in a brass tube and seals it with sixty [i.e., many] seals and suspends it around his left arm;
and the proof-text is. A wise man's heart is at his right hand; but a fool's heart is at his left.(Eccl. 10:2)"
(Ok, as a left-handed person, I am insulted. But let’s continue:)
"He acquires as much wisdom as he desires, studies as much as he desires, and [then] eats the other half, for if [he does] not, his learning will vanish."
A charm which involves an action to turn it on (eating half), wearing an amulet, and then eating something (the other half) to turn it off.