gxseries Posted September 2, 2012 Report Share Posted September 2, 2012 I'm quite shocked that this happened but if you say that this is cleaned, 10 out of 10 will say so. But if I said I was conserving this coin by putting it in olive oil for about a week or so, would you believe me? This was what it was originally It's a rather scarce coin and thought if I could get rid of the verdigris, it would be better. But not when it looks cleaned. I didn't do anything special to the coin - just took it out from the container that had olive oil and washed it with water. But when I pat it dry - patina just stripped off. Came as a shock to me. It's not the first time I've conserved copper coins - I have some coins that have been in olive oil for more than 1 month and one up to almost a year and I have changed the oil regularly. This one took me as a big surprise - it shouldn't have happened but it CAN happen. I guess the moral of the story is to look at your coins a bit more often if you are conserving. It's a shame, this is one coin that I cannot upgrade easily or even downgrade to start out with. Quote Link to comment Share on other sites More sharing options...
DJB Posted September 2, 2012 Report Share Posted September 2, 2012 Nice coin. I don't think it looks that bad. You did what felt you had to, to prevent the coin from degrading. On another subject. Is that a die clash error I'm noticing. I'm seeing a shadow image of the reverse pattern showing in the lower right corner of the obverse. Interesting. Quote Link to comment Share on other sites More sharing options...
gxseries Posted September 3, 2012 Author Report Share Posted September 3, 2012 It's not a die clash DJB. It's overstruck over Xinjiang 1929 10 cash like this one: Quite a hard coin to find to be honest. Quote Link to comment Share on other sites More sharing options...
SMS Posted September 3, 2012 Report Share Posted September 3, 2012 <P>The only difference between "cleaning" and "conservation" is intent, although certain powers that be have propagated otherwise these past years. "Conservation" has little to nothing to do with being a "professional". "Conservation" and "cleaning" are essentially the same mechanism.<BR> <BR> <P>That said, not all attempts to conserve succeed. Take a look at <A href="http://kth.diva-portal.org/smash/get/diva2:455772/FULLTEXT01">this dissertation</A> (doctoral thesis). Read the subsection entitled "2.1 Atmospheric corrosion of copper" as it explains the process of the patina. Remember, the patina protects the surface.<BR> <BR> <P>If you have time, give the entirety of the thesis a good read.<BR> <BR> <P>There are a number of factors that could determine your conservation results. Chemical reactions vary in time and intensity based on a number of factors including such things as the level of acetic acid in the olive oil you used (which itself has many factors including crop production and manufacturing methods). Regardless of the frequency in which you changed the oil, other conditions (including humidity) could also affect the way the copper oxidizes in the olive oil.<BR> <BR> <P>"Conservation" is a gamble (even for the "professionals"). Quote Link to comment Share on other sites More sharing options...
thedeadpoint Posted September 4, 2012 Report Share Posted September 4, 2012 Warning: 1.5 MB PDF linked above. Quote Link to comment Share on other sites More sharing options...
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