I'm in the process of better cataloguing the FF Ancient collection and as part of that am re-photographing each coin. I pulled this coin out yesterday and when I flipped it over I noticed a green powdery spot. I hit it with a toothpick and it all flaked off. This is what it looked like post toothpick. Reading through some posts, I should soak it in distilled water for a bit and then give it a scrub right? I don't want it to spread any further. Caracalla Tetrassarion Pautalia, Thrace Obverse: ΑVΤ Κ Μ ΑVΡΗ ΑΝΤΩΝΕΙΝΟC, laureate bust right Reverse: ΟΥΛΠΙΑC ΠΑΥΤΑΛΙΑC, eagle with wings spread, holding wreath in its beak 17.29g/29.7mm Here is the coin when I got it back in April of last year. Sans bronze disease.
I have never had any success treating BD. If it's a coin I don't want to discard I pop it in a capsule and keep it apart from the rest of the collection.
It's in a flip in a pocket of a binder. I imagine that it is pretty well isolated from the rest of the coins. It cost less than $3 so it's not super valuable but I do like it.
At three bucks you did well! I'm a low-budget guy myself. My guess is that somewhere in the chain of ownership somebody else cleaned up some BD and now it's coming back. The spot where it appeared next to the eagle's wing is already eaten away in the pre-BD photo, which makes me think it's just an in-between-BD photo.
Yep. Distilled water as soon as possible and let sit for a couple days before you break out the old soft bristles. Cool coin and fun type. The purple splotches show that is had bd issues before.
You might try an initial soak with household baking soda in solution to neutralize the acidic component of the reaction. This would be a 'poor mans' version of the sodium sesquicarbonate treatment that you can find in other threads. The key after the distilled water is complete drying in a warm oven and keeping the coin dry afterward. Humidity is the enemy with BD.
Well he is soaking in a small container of DW right now. If that doesn't work, I will try the baking soda solution. The coins have been in flips in a binder in our house so not in any kind of humid location. For the oven part, low and slow? I could put it in our toaster oven for awhile. Mrs FF may give me grief if I use the regular oven to bake a single coin haha.
My strategy: Dig it off, or out of there, with a toothpick or a pin, carefully. Put it on a piece of aluminum foil and bake it in the oven 375 degrees for 30 minutes. Let it cool but treat with Verdicare while still warm. I've never had any problems with baking though it can change the color of some patinas. Unless you make your own, the distilled waiter treatment is flawed. That's because store bought distilled water is rarely 100% what it says it is. Plastic flips are a great breeding ground for bronze disease judging from the number of infected coins I've bought in flips. Of course some bronze disease is terminal if it's gotten way down into a porous coin. I recently bought a coin that had bronze disease under the patina though maybe this coin was painted to disguise it. I only use sodium sesquicarbonate in extreme cases. (That's a whole 'nother lesson.) Some people are so freaked out by BD that they will dump an expensive coin with a couple of spots on Ebay for pennies. When you can proudly say, "Bronze disease doesn't scare me!," you have truly become a serious ancient coin aficionado. If you disagree with anything I've said then go with what you know. I don't give a fig.
After reading a post by, I think, @Roman Collector recently, I put a couple of AEs in distilled water - just distilled water. Nothing else. So far, it is working really well. The Trajan looks cured; the Vespasian still has some green spots, but they may not be BD. It's only been four or five days, so I am going to keep soaking the Vespasian. A couple years ago I tried the baking in the oven method - it seemed to work too, but badly discolored the coin. Good luck!
Gee, I don't know. Since you paid only $3 for it and a gallon of distilled water costs at least $1.50 . . . Seriously, though. Try changing the water every few days. Do this for at least 3 weeks or so. I don't think baking soda will hurt your coin, and it might speed up the process. There's a chance it might leave a powdery film on the coin, but it shouldn't be difficult to remove this.
I still have some distilled water since my daughter and I have been working on cleaning a group of LRBs we got at the beginning of the summer
Bronze disease can't be be cured but it can be interrupted and prevented from recurring. Bronze disease behaves in the manner it does because it is not a single chemical reaction but a repeating series of reactions where one feeds on the byproduct of another in an endless cycle. The basic reactants are copper, oxygen and chlorine (from water). Put simply, a coin with bronze disease is eaten away by hydrochloric acid. The object will eventually be completely consumed if not treated. Treatment involves breaking the cycle and then depriving the reaction of one of the essential ingredients - water. Even the small amount of water in the air on a humid day is enough to start the reaction again. This wikipedia article covers the basics, including treatment. One method commonly used by collectors involves sodium sesquicarbonate which will neutralize any remaining acid and convert reactive cuprous chloride to relatively inert cuprous oxide. Sodium bicarbonate (baking soda) will similarly neutralize the acid but does not do everything that the sesquicarbonate does. As noted above, the baking soda bath can have unpredictable results on the patina if left too long and/or not completely dissolved. Maintenance involves regular inspection and keeping the object as dry as possible. Good luck!
