randazzo1
Bronze Member
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Hi all --- We've been digging at a new site in central NJ. The site had a house on it built circa 1850. All that is left is the foundation and a few pads from outbuildings. We've turned up one 185? seated half dime and a few pieces of 1900's silver as well as the usual assortment of trash and clad coins. I was last out there yesterday (power is out and there is no gasoline to be had anywhere here --- so there isn't much to do!). We found about a dozen of these square copper plates that we originally mistook for electrical junction covers or something of the like. They are however some sort of printing plate or etching plate. The largest is about 4x4 and the smallest 1.5x1.5 (inches).
The ones we can actually see all depict dogs. I am wondering what era they are from and what exactly they are for - newspapers? books? Also - it would be nice to know how to use them. Finally, and perhaps most importantly - we are trying to figure out what the presence of these things means for the site --- was this a common item to have in household at some point? I am totally unfamiliar with these types of items.
We figured out a pretty good method for cleaning them for anyone who is interested. The first one I scrubbed with a brush and then a sponge. This technique destroys the delicate copper cells. The next one we put in an ultrasonic clock cleaner for about 1/2 hour. Not much of a result. We experimented with varying solutions of nitric and hydrochloric acid. Best result is one table spoon of hcl in about 2 cups water. Add the solution to a pan and cook the plate for about 1 minute on high heat (I don't know if this is safe so do it at your own risk@!@!).
Posted below are photos of some of the plates and before and afters of the cleaning.
Thanks in advance for any advice anyone has on what they are, how to use them, and what they were used for.
The ones we can actually see all depict dogs. I am wondering what era they are from and what exactly they are for - newspapers? books? Also - it would be nice to know how to use them. Finally, and perhaps most importantly - we are trying to figure out what the presence of these things means for the site --- was this a common item to have in household at some point? I am totally unfamiliar with these types of items.
We figured out a pretty good method for cleaning them for anyone who is interested. The first one I scrubbed with a brush and then a sponge. This technique destroys the delicate copper cells. The next one we put in an ultrasonic clock cleaner for about 1/2 hour. Not much of a result. We experimented with varying solutions of nitric and hydrochloric acid. Best result is one table spoon of hcl in about 2 cups water. Add the solution to a pan and cook the plate for about 1 minute on high heat (I don't know if this is safe so do it at your own risk@!@!).
Posted below are photos of some of the plates and before and afters of the cleaning.
Thanks in advance for any advice anyone has on what they are, how to use them, and what they were used for.