From time to time, you will hear bottle collectors refer to the term “slug plate” in their description of a particular bottle, usually one that is BIMAL (“blown in mold applied lip”). In his Glossary of Antique Bottle Terms, Reggie Lynch defines a slug plate as a “metal plate inserted into a bottle mold to provide product specific info to an otherwise generic mold. Also refers to the mark left on a bottle by such a plate.” Slug plates were fairly extensively used by bottle manufacturers probably as a cost saving measure to allow them to customize a particular bottle for a patron without having to create an entirely new mold.
Slug plate marks turns up on a variety of Warner’s Safe bottles beginning with Warner’s intial offerings, which were manufactured for him by the Chambers Works in Pittsburg. See Warner’s Safe Cure: The Early Bottles and Warner’s Safe Cure: Bitters. Warner’s early bottles featured, among other things, a full slug plate. Apparently, when Warner ordered a particular type of bottle, whether it be his Safe Kidney & LIver Cure or his Safe Bitters, the Chambers Works simply put that particular slug plate in the generic mold and turned out whatever quantity was ordered. The imprint of the full slug plate is obvious on the face of the bottle and serves to mark it as one of his early variants valued by collectors.
If you think the slug plates were limited to Warner’s early Rochester bottles, you would be wrong. Although the full slug appears unique to the early bottles, Warner and those from whom he purchased his bottles, used slugs in later bottles. It appears that those slugs served two principal purposes, they allowed Warner to alter that name of a particular product contained in a bottle (e.g. Nervine for Safe Cure) and to alter the foreign office using the mold (e.g. Frankfurt for London). As was mentioned earlier, the bottles for the Melbourne office were initially manufactured in the United States and shipped to Australia given the primitive state of bottle manufacturing at that time. A couple of examples that demonstrate Warner’s use of slug plates in this fashion are the Frankfurt half pint Nervine, which was clearly slugged from the mold of the London half pint and bears the rectangular slug mark to prove it. Another is the early Melbourne bottles which show that the word “Melbourne” is slug plated in, probably from a mold otherwise used for Rochester or perhaps London bottles. These are but a couple of examples and others exist. Indeed, they represent an interesting and, undoubtedly unintentional, fingerprint of bottle makers of the time.
Thanks to Ed Ojea for the photos comparing the half pint Frankfurt with the half pint Londons, which clear show the slug marks.