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<p>[QUOTE=&quot;-jeffB, post: 2004049, member: 27832&quot;]This doesn&#039;t sound right to me.</p><p><br /></p><p>IF the AT is produced by adding a colored foreign material to the coin, and that material is acetone-soluble, or bound to the coin by something that&#039;s acetone-soluble, then, yeah, acetone will take it off.</p><p><br /></p><p>But natural toning, and many forms of artificial toning, consists of a surface layer of sulfide or oxide on the coin. These surface layers are very, very thin, and the color comes from interference effects as light passes through the layer. They&#039;re also <i>chemically bound</i> to the surface, and they&#039;re <i>not</i> acetone soluble. Acid dips will remove them, by reversing the chemical oxidation that first formed them, and/or removing both the layer and the metal beneath.</p><p><br /></p><p>So, to your original points:</p><p><br /></p><p><i>Some</i> forms of AT can be removed by acetone -- dyes, enameled layers, and so on.</p><p><br /></p><p><i>Many</i> forms of AT <i>can&#039;t</i> be removed by acetone -- those done by baking, sulfides, and so on.</p><p><br /></p><p>Natural toning, as well as many forms of AT, consists of a &quot;substance on top of the coin&quot; -- a sub-microscopic layer of sulfide or oxide. This layer won&#039;t come off with acetone; it will come off with dip (acid/reducing agent), or by physically scouring it off. And if the chemical reaction goes far enough to <i>penetrate into</i> the coin, it&#039;s corrosion, not toning, and ruins the coin.</p><p><br /></p><p>Greg, you&#039;ve dealt with toners a lot more than I have. Does this make sense, or am I confusing myself here? I had thought most AT was done by heat or by chemicals that mimic the natural process; do you find that most AT coins lose their color in acetone?[/QUOTE]</p><p><br /></p>

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