I posted this bronze coin of Byzantine Emperor Anastasius in a reply a few days ago. I was advised to treat the bronze disease affecting that coin, as soon as possible. So I immediately soaked it in distilled water and then used the hair drier to dry it. Then I got this result. I do appreciate all your comments and advices.
I don't think that BD is an actual disease! Here is some info. Distilled water alone may not be the best way to resolve the issue. I want to share this webpage with you - https://en.wikipedia.org/wiki/Bronze_disease
It is hard to tell without having seen the coin in its original condition. Soaking usually takes a few days or weeks. You want the minerals to leach out of the coin into the water. You then have to make sure you can seen no sign of disease after picking at what was there. I dry stuff out using those silica gel packets, the sort that you find in new handbags and cameras. Blowing it with the hairdryer might dry off the surface but if there is moisture within the coin it is unlikely to dry that.
I was just going to post this link. It is HIGHLY unlikely that soaking in distilled water, followed by drying, will eliminate true bronze disease. If you understand the chemical equations on the Wikipedia site, you'll see that the chemical reaction is self-perpetuating unless (1) water is eliminated from contact with the coin, or (2) oxygen is eliminated from contact with the coin, or (3) the reaction exhausts itself by running out of copper. So if the green has been eliminated from the surface of your coin, it's probably not bronze disease.
I have treated several coins with Bronze Disease, I never consider them cured, only in remission. Once I am sure I have tackled the problem the best I can, I use Verdi-care.
I should add that you can also stop bronze disease by removing the chloride ions from the coin but this is very difficult. To quote Wikipedia: "As it relies upon the presence of chlorides, water, and oxygen, the absence of one of these three halts the progress, although any damage done is irreversible. Treatment for the condition typically involves physical removal of the chlorides (through scrubbing), chemical or electrochemical removal, and then isolating the object from oxygen, water, and future chloride contamination using an airtight container or a wax coating. These treatments may also remove any patina, loss of which is often seen as undesirable to collectors and conservators but is preferable to loss of the object."
Any advocates for air tight, NGC-like slabs with nitrogen? In theory, it would halt the chemical reaction; as nitrogen shouldn't react with the chlorides. Several museums preserve metal and paper artifacts with a similar construct. May be the exception for those who dislike slabs, to preserve a coin.
None of the slabs are airtight, as evidenced by toning that happens while slabbed. For BD, I soak in Verdicare, scrubbing off larger bits with a sharpened bamboo stick, and after it dries out coat in Ren wax and put in safety flip. I have had very good luck over the years with this treatment.
I am referring to something that doesn't exist yet (as far as I know.) There was a discussion about the idea to create something similar on coincommunity a few years back.
I mechanically clean the coin with a syringe needle tip and using a magnifier glass to produce minimum intervention. After soaking several weeks in Distilled water, I take it out and gently rub it with isopropilic alcohol which mixed with water makes it evaporate at room temperature without any doubt. Then another period of "quarantine" and then, if nothing happened, I wax it with Renaissance wax.
The problem with distilled water is its exactly what the BD needs to thrive. I am a fan of it in all other cleaning applications except removal of BD. Just my opinion.
i've had some success with distilled water. i scrape off the BD as best i can, then soak for a couple of day sin DW. Need to scrape again? change the water and repeat. look good? dry it, then apply verdicare. is the back have removable dirt? it looks like it. that may trap moisture as well. i'd clean it , changing the distilled water every time you clean until it you are happy...then verdicare it. do you have any verdicare 7C? or can you get it?
