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<p>[QUOTE=&quot;Oldhoopster, post: 7972075, member: 84179&quot;][USER=74574]@serafino[/USER] Acetone will not react with copper under most conditions.&nbsp; There is one scientific paper that reported when acetone is allowed to completely dry (no rinse) and exposed to light and humidity, after 18 hrs copper acetate was detected.&nbsp; They suggest that that copper can act as a photocatalyst In the <b>slow</b> (their word) formation of acetic acid.&nbsp; The acetic acid would then need to react with the copper.</p><p><br /></p><p>If you use a short soaks, don&#039;t let the acetone completely evaporate, and rinse in distilled or deionized water (not tap) immediately after removal from the soak (acetic acid is very soluble in water) you&#039;ve eliminated all the conditions for any potential copper acetate formation.</p><p><br /></p><p>Link to the SUNY Stony Brook paper if anybody wants to make their own conclusions.</p><p><a href="https://vdocuments.site/photochemical-breakdown-of-acetone-on-copper.html" target="_blank" class="externalLink ProxyLink" data-proxy-href="https://vdocuments.site/photochemical-breakdown-of-acetone-on-copper.html" rel="nofollow">https://vdocuments.site/photochemical-breakdown-of-acetone-on-copper.html</a></p><p><br /></p><p>Many members have reported that they have first hand knowledge of copper toning after an acetone soak and I don&#039;t discount that.&nbsp; However, could that have been caused by the soaking method (long soaks, evaporation, inadequate rinse) or even incomplete organic removal or contamination residue left from poor rinsing that reacted to form the toning?&nbsp; You can&#039;t say for certain, but the science&nbsp; says that acetone is safe on copper except in some very specific circumstances</p><p><br /></p><p>Also, I use acetone regularly on most newly purchased coins primarily for PVC plasticizer residue removal (Never know how a coin was previously stored, and by the time you see the green slime, damage has already occurred). I&#039;ve estimate I&#039;ve done a few hundred copper coins in the last 30 years ranging from cruddy low grade stuff to MS Lincolns.&nbsp; Using short soaks and rinsing, I have never had any color changes.&nbsp; I think acetone is a very useful part of a numismatists tool box, especially for removing PVC plasticizer residue.&nbsp; People may chose not to use it but I feel that presenting all the information will help people make an informed choice.[/QUOTE]</p><p><br /></p>

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