Help!! Bronze Disease / Verdigris Destroying My Ancients!

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Author	Replies: 5 / Views: 2,341
DenverPio New Member United States 9 Posts	Posted 07/29/2020 7:08 pm Hi folks, I have been collecting ancient coins for roughly 5 years. My collection is primarily Byzantine and Late Roman bronze folleis, with a few silver and gold mixed in for good measure. I recently began to notice the dreaded, horrifying verdigris/bronze disease appearing on a large number of my coins. It sometimes appears as neon green dots on surfaces, and other times like a fuzzy blue-green coating. I need help to remedy this problem now before it spreads and annihilates my entire collection! They are stored in a Beba chest of 10 drawers in a cabinet with a door. I have placed weather stripping all around the crevices/openings of the cabinet and this has brought down the humidity to ~40%. I live in an extremely humid climate in an older home which has difficulty managing the overall humidity--so 40% is much lower than if they were stored elsewhere in the home. Silica packets strewn throughout the cabinet and a dehumidifier have not been able to bring the relative humidity lower than 40%. I have read extensively and some sites suggest a complicated chemical process to remove verdigris using BTA (C6H5N3). This is not really an option for me. On the other hand, I've seen that some people do olive oil soaks, which may work, but can also damage the patina of coins; some of them have nice sand patinas or very fine surfaces. Some also use acetone--has this worked for anyone? I know that there are also some products available on the market, but the one product designed to remove verdigris seems to be out of stock worldwide with no more supply being produced. I truly appreciate any help you might be able to provide. It's devastating to see my collection of coins that have survived centuries being degraded before my very eyes. Thank you! *edited for spelling error Edited by DenverPio 07/29/2020 7:22 pm Report this Post to the Staff

Seeker55 Pillar of the Community United States 634 Posts	Posted 07/29/2020 7:31 pm Here's an article with steps to address bronze disease. https://www.forumancientcoins.com/n...ze%20Disease The solution of mixed sodium carbonate (washing soda) with sodium bicarbonate (baking soda) in distilled water is easy and inexpensive to make and is a helpful soak to remove green corrosion and stop its progress. The soaking can be done for a few days at room temperature instead of the hot water method described. Edited by Seeker55 07/29/2020 7:34 pm Report this Post to the Staff
sel_69l Bedrock of the Community Australia 21786 Posts	Posted 07/29/2020 8:46 pm Arguably the best treatment for bronze disease on ancient coins. Can be used for rare moderns as well. Remember, social distancing is essential even for coins, when it comes to bronze disease - store them in isolation. Report this Post to the Staff
Spence Moderator United States 34409 Posts	Posted 07/29/2020 9:20 pm @dp, from what I understand (and what @sel is saying above) is that BD travels from one coin to the next. It sounds like your coins are in trays in a cabinet. Cool to look at for sure, but hard to keep coins separated. Consider 2x2s for storage of your coins once you have them treated. "If you climb a good tree, you get a push." -----Ghanaian proverb "The danger we all now face is distinguishing between what is authentic and what is performed." -----King Adz Report this Post to the Staff
DenverPio New Member United States 9 Posts	Posted 07/29/2020 9:48 pm Okay, I can definitely try the cleaning suggestion. Thank you! As for distancing, what is a safe spacing/separation? The issue with 2x2s is a) storage and b) many of them have PVC. I know that there are PVC-free 2x2s, but the other issue is the irregular size of ancients. Many coins, even of the same issue (e.g. Justinian's folleis) will be significantly different sizes, thus hard to standardize the 2x2 opening. The trays are archival-quality material, so I'd love to stick with them if possible. Thanks again!! Report this Post to the Staff
Seeker55 Pillar of the Community United States 634 Posts	Posted 07/30/2020 10:03 am Quality 2x2 holders should be made with Mylar, a very inert plastic safe for long-term coin storage. You can easily buy Mylar 2x2 holders with a variety of hole sizes from any coin supply place. Edited by Seeker55 07/30/2020 10:16 am Report this Post to the Staff
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