Hi all, I have this small coin from Carthage... it has some mineralization covering much of the detail on each side. I seem to remember that there are some here that have methods for removing these deposits while not stripping the patina. I'd rather leave it than ruin it but I was hoping I may get some cleaning tips beyond distilled water and a brush. Additionally... If anyone knows an attribution or reference for one of these around 16mm and 3.2 grams, I'd appreciate it was well... All I'm finding is references for similar coins twice the weight or more. Zeugitania, Carthage AE16. 3.2 grams Head of Tanit left, wreathed with corn, wearing earring Horse standing right, looking back left, foreleg raised. Thanks!
SNGCop 273 Carthage, AE16, c. 241-221 BC, Head of Tanit left / Horse right, head turned. or, if there is a star above the horse SNGCop 316 Carthage AE18. c241-221 BC, Head of Tanit left / Horse right, head turned, star above.
It looks like the surface of your coin has reacted with its environment in such a way that its chemistry has changed. This is not just a simple case of dirt or something stuck on the surface. Your surface has changed. There is a product called Verdi-Care that you might consider. It has been discussed in this forum a couple of times before: https://www.cointalk.com/threads/verdi-care.222408/ https://www.cointalk.com/threads/verdi-care.257286/ Here's a source for it if you're interested: http://www.wizardcoinsupply.com/products/verdi-care.html I've never used this product, and so I have no opinion about it. Electrolysis is another possibility. It will remove the green build-up, but with two (actually one and a half) downsides: 1) The surface of the coin under the green build-up has been eaten into slightly, a result of the copper oxidizing. Removing the green stuff will reveal a rough, pitted surface. 2) You will wind up with a bright, shiny coin that looks unnatural for a coin so old. The reason this is really drawback 1.5 rather than 2, however, is that over time the coin will gradually re-tone and darken. It will take a few years, but eventually it will look nice again (except for the rough surface). A third possibility is to take a scalpel and scrape away the build-up, preferably under a stereo microscope. This is often called "smoothing." Some collectors object to it, others don't. A fourth possibility is to enjoy your coin the way it is right now.
It’s showing it's age! It’s a beautiful coin, nonetheless. Only ancient's collector’s like us can appreciate the beauty!
I like the looks of the coin ... congrats Ummm, to me, it merely looks like solid green crusties (hopefully) Good luck if you decide to remove them, or if you decide to go that Verdi-care route (I have a bottle that I use if any of my coins ever get the "powdery green" disease) ... but again, I kinda like my coins to have bit of grunge on 'em
Sodium bicarbonate solution will also probably strip the verdigree and leave at least some of the patina. But you'll want to monitor it every few minutes and pull it out and soak in distilled water BEFORE you think it's done. I recommend this because it's less radical than ammonia (don't go there) or electrolysis. Again, no guarantees.
Thanks everyone! Yeah I like the coin and intend to play it pretty safe if I do try anything. There just seems to be a lot of great detail obscured by the thick, very hard green deposits on the face and horse. I had read of a few others successes removing these types of incrustations and was thinking I'd get some opinions about what may work.
