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<p>[QUOTE=&quot;Oldhoopster, post: 2982473, member: 84179&quot;]I&#039;ve been using Acetone to remove PVC residue from coins ever since they stopped making CFC113 in the 80&#039;s and never had a copper coin change color. As far as I&#039;ve been able to tell, the only research indicating that acetone can directly react with copper is the following paper:</p><p><a href="http://www.stonybrook.edu/vescalab/research/research7.html" target="_blank" class="externalLink ProxyLink" data-proxy-href="http://www.stonybrook.edu/vescalab/research/research7.html" rel="nofollow">http://www.stonybrook.edu/vescalab/research/research7.html</a></p><p>They soaked copper in acetone for 18 hrs, and after the acetone evaporated, found copper acetate crystals and an odor of acetic acid. The authors even comment that the formation of acetic acid is a slow reaction. Do you know of any additional research that discusses this reaction, or the reaction rate for the formation of acetic acid in the presence of copper? Dipping a copper coin in acetone for a few seconds/minutes and then rinsing, is a lot different than allowing it to soak and evaporate over 18 hrs. </p><p><br /></p><p>Unless there is something in the reaction rates that indicate a short soak would expose a coin to enough acetic acid to cause discoloration, I really wouldn&#039;t want to trade the risk of using a using a potentially hazardous solvent like dichloromethane for a much safer solvent like acetone.</p><p><br /></p><p>Since you&#039;re a chemist, I&#039;m sure you&#039;re proficient with the safety procedures for handling this type of material and don&#039;t dispute that it gives you excellent results. But how are the vast majority of CT members, who aren&#039;t chemists, going to make an informed decision about the risks of using a hazardous solvent versus the risks of discoloring a copper coin with acetone, especially since the latter risk appears to be insignificant?[/QUOTE]</p><p><br /></p>

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