We haven't exactly been inundated with emails identifying these mystery objects.
They are, of course, hickey pickers, which are hand tools used by printers to remove the minute particles of hard ink or paper fibre which can sometimes work their way onto the surface of a lithographic printing plate or blanket while the press is running.
These blemishes – or hickeys – can result in a 'bullseye' (or 'doughnut' if you're American) appearing on the printed sheet – basically a small uninked spot in the printed image.
Hickeys are widely considered to be imperfections. Part of the unholy alliance which also includes catch-up, scumming, showthrough, misregistration, poor fit and setoff – all designed to thwart the printer and aggrieve the client. But does the much maligned hickey deserve such a bad press?
These days letterpress printing is admired for it tactile quality and the 'bite' it gives to the printed piece – yet in the past letterpress minders would go to great lengths to prevent 'bite', applying and removing layers of tissue paper to the underside of metal type in order to retain the smooth surface of the printed sheet. The debossed effect, or 'bite' which gives letterpress printing a unique characteristic was, back then, considered a flaw.
Hickeys today are thought of as flaws in the print process but such flaws, in rare doses, can add something unique to otherwise identical copies.
The Inverted Jenny stamp and the Wicked Bible are result of errors in the printing process – errors that differentiated them, made them more desirable. You don't get 'bite' in lithographic printing and you don't get hickeys in digital printing – so when digital printing eventually replaces litho (as litho replaced letterpress) will future afficionados of print ephemera think of hickeys in an entirely new light?