I’m in several book clubs. One of these is engrossed in the reading of David Graeber’s Debt: the first 5000 years. One of the topics there is the evolution of what coinage or currency is, how it attains its value, etc.

Of course, once you see one thing, you see it everywhere. From Catherine Nicholson’s review of a book on Tudor era childhood (emphasis added):

As the archaeologists discovered, the hollow resonance chambers running beneath the choir stalls, designed to enhance the acoustics of the space, had become a convenient repository for floor sweepings, food scraps, and all manner of childish possessions: wooden-handled penknives and inkwells fashioned from chunks of the crumbling sandstone walls; tokens used in teaching arithmetic; arrowheads for target practice; animal bones from midday meals; belt buckles; a metal mouth harp; a few clay and stone marbles; the frame for a pair of spectacles; and a single molar, considerably worn but with root intact, lost from the mouth of a child between the ages of nine and twelve.

But the bulk of the Whitefriars inventory, by far, consisted of tiny pieces of metal: dozens of hooks; hundreds of tags, aglets, and lace ends; and an extraordinary quantity of pins—1,575 in all—ranging in diameter from fine dressmaker’s pins to sturdy tacks. In a report on the excavation, one of the archaeologists notes that similar stashes of pins had been found in sites in Southampton and Rickmansworth, “but not in these quantities,” and concludes, “It seems likely that they relate to the wearing and pleating of ruffs.” In his new study, Tudor Children, the British historian Nicholas Orme advances an alternate theory. Lacking access to coins, he argues, children in sixteenth-century England invented currencies from what was at hand: pebbles, nuts, cherrystones, seedpods, and any available bit of metal.