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FORVM`s Classical Numismatics Discussion Board  |  Numismatic and History Discussions  |  Coin Photography, Conservation and Storage  |  Topic: Problems with humid air and corrosion of coins 0 Members and 1 Guest are viewing this topic. « previous next »
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Author Topic: Problems with humid air and corrosion of coins  (Read 1640 times)
jalmvs
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« on: August 27, 2008, 09:29:21 am »

It has happened to me some times, I buy a bronze coin which is located in Europe or U.S. and when it arrives to my tropical country it begins to corrode after some days or even some hours.

I place them inside the cardboard holders and after some days, dusty green spots pop in some places around the coin. Carefully I've removed the spots with a needle but they appear after some hours.

What can I do to get rid of that green dust and to neutralize the corrosion.

Thank you for any advice.
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slokind
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« Reply #1 on: August 27, 2008, 03:17:50 pm »

Southern Louisiana, where I live, also is quite humid, Costa Rica probably more so, but when a coin develops full-blown bronze disease (which, from your description, I can hardly doubt your coins have) in the space of days or weeks, I must wonder whether the coins hadn't been superficially cleaned, but not effectively treated, for pre-existing bronze disease before they were photographed, sold, and shipped.  I have had to be careful of my bronze coins, of course, putting sachets of silica gel in all the storage boxes and not economizing on the air conditioning in the rooms where they are kept.  With these precautions, only coins that arrived already with bad symptoms have been troublesome.  I'll find the page with a coin of mine that had bad BD, with photos of progressive treatment.  Pat L.
http://www.forumancientcoins.com/board/index.php?topic=43730.0
Be sure to read all 8 replies.  Don't try quick fixes.  Also see other threads on bronze disease, but, as I said, drastic, "sure-shot" fixes are likely to make matters worse.
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romeo
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« Reply #2 on: September 19, 2008, 06:30:42 am »

some sellers put there coins in the oven before photgraphing them and again just before sending them, this give a short term cure but it tends to only last for a few days and darkens the coins, then the poor buyer a few days later finds the coin has got spots of fluffy green. one seller on ebay did this to my wife a couple of times, she got a refund but not before the seller told her to put them in the oven!


(i mean he put the coin in the oven- not my wife) Grin
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bruce61813
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« Reply #3 on: September 19, 2008, 07:33:00 pm »

Read through the article posted in the Numiswiki http://www.forumancientcoins.com/numiswiki/view.asp?key=Bronze%20Disease,it does explain what is happening to the coins.

Unfortunately there is no method of predicting where and what coins will develop BD. But ones from extreme desert areas tend to sow a high proportion. Also nice deep green patina is not a protection. I had a beautiful Probus coin from a dealer in Australia, develop BD about one year after I obtained it.

Bruce
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too many coins - too little time!!
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FORVM`s Classical Numismatics Discussion Board  |  Numismatic and History Discussions  |  Coin Photography, Conservation and Storage  |  Topic: Problems with humid air and corrosion of coins « previous next »
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