No, me neither! Although in saying that, it was probably referred to in the bible for finishing: A Polishers Handbook, by Neil Ellis. If you haven’t read or come across this before, it is well work the small investment. You can order it here.
And no, there is nothing behind that endorsement, other than it being highly recommended, and essential reading matter.
In saying that, seeing as there is a new edition (much newer than my current copy), and I don’t remember whether polissoirs are mentioned, it might be time for me to be reacquainted with it as well.
Anyway, back to the polissior.
It is an 18th century tool (if not from even earlier) for applying, abrading and polishing a wax finish. Simply made from a tightly bound bundle of organic material (such as straw), it is then dipped in molten wax to charge it up, and then (once cooled) rubbed over the surface of the timber.
The polissior both burnishes the surface, and applies the wax, driving it into the pores (where open grain timber is used).
The excess wax is removed, either with a wooden scraper (or the other end of the polissior), then the surface buffed with a cloth.