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<p>[QUOTE=&quot;robinjojo, post: 4427630, member: 110226&quot;]Bronze disease appears as a light green powdery area on a bronze coin.&nbsp; From what I could see from the images, I didn&#039;t see any overt signs.&nbsp; </p><p><br /></p><p>Soaking in distilled water, as already mentioned, over a period of several weeks will tell whether or not the coin is afflicted with this problem. You have some pretty encrusted coins, so some of that material will likely soften and fall off the coin during the soaking period.&nbsp; Distilled water will remove the green powder, but unfortunately it is not a cure.&nbsp; Bronze disease could very well show up again after this process, so the coin needs to be monitored.</p><p><br /></p><p>For coins with recurring bronze disease, there is a more high risk treatment, and I don&#039;t recommend this method for high value coins.&nbsp; A couple of years ago I got a lot of Byzantine bronzes from auction.&nbsp; The coins have a nice desert patina, as is often the case with this type.&nbsp; Unfortunately a nice Justin II and Sophia follis had bronze disease on the edge, and also in the middle of the reverse.</p><p><br /></p><p>I soaked the coin in distilled water and added a small amount of sodium sesquicarbonate.&nbsp; Almost immediately the desert patina dissolved, revealing an even dark brown patina on both side.&nbsp; I left the coin in the bath for several weeks.</p><p><br /></p><p>Upon removing the coin the bronze disease areas appeared clear, but just a week or two later the disease returned, so clearly the corrosion process in the bronze was continuing.&nbsp; I noticed that the bronze disease was developing in areas where there was still some patina remaining.</p><p><br /></p><p>I proceeded to the next step, and, as I said, this step should not be followed with rare, high value bronzes.&nbsp; Using a toothpick, I dipped one end into a jar of Naval Jelly.&nbsp; This is a powerful rust remover.&nbsp; I applied it only on the spots where the bronze disease was coming back.&nbsp; Effectively I was removing all surface deposits and going down to the bare metal.&nbsp; I left the Naval Jelly on the spots for around 10-15 minutes, then washed the coin with distilled water.&nbsp; I then put the coin back into a distilled water bath, leaving it there for a couple of weeks.&nbsp; Upon removing the coin I set out on a counter for monitoring.&nbsp; I&#039;m still monitoring it.&nbsp; So far the bronze disease has not returned, although now I have a coin showing exposed metal on the edge and in the center of the reverse.&nbsp; These areas are slowly retoning.&nbsp; That process could be sped up with liver of sulfur, but I don&#039;t want to destabilize the surface any more than I already have. As a recovering &quot;patient&quot; this coin will require constant scrutiny.[/QUOTE]</p><p><br /></p>

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