Burnisher
2 of the 7 encyclopedias on this shelf carry an entry for Burnisher. Both are reproduced below, so you can see where they agree and where they differ.
American Watchmaker and Jeweler (1892)
A polished steel or agate tool used for glossing the the surface of metals. Fig.44 is a jewel burnisher. The article to be burnished must be first freed from all scratches, for scratches would only be brought out more prominently by the use of the burnisher. The burnisher must be kept highly polished or you cannot expect to do good work with it. Saunier gives the following method of re-facing a burnisher: Prepare a dry smooth piece of wood, rather thick, and of a width equal to the length of the burnisher. On this board carefully glue a piece of emery paper of a fineness corresponding to the degree of cut required, stretching it as even as possible, and turning the edges down towards the under side. Then lay the board on a firm smooth surface, resting a weight upon it, and allow it to dry. In using this lap, it is fixed or allowed to rest against the side of the bench; holding the burnisher with two hands at its extremities, the workman places himself at one end of the board, and draws the burnisher along it towards him, maintaining the surface quite flat and applying considerable pressure. On reaching the nearer end, raise it, and after again placing it on the furthest end, draw towards the body, and so on. By proceeding in this manner all risk of rounding the angle will be avoided.
Collier's New Encyclopedia (1921)
a tool for smoothing or pressing down surfaces to close the pores or obliterate lines or marks. The engraver's burnisher is made of steel, elliptical in cross section, and coming to a dull point like a probe. Some burnishers are made of the canine teeth of dogs. Burnishers of bloodstone are used for putting gold leaf on china ware. Agate burnishers are used by bookbinders. The gilder's burnisher is of agate or porphyry.