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<p>[QUOTE=&quot;desertgem, post: 1505311, member: 15199&quot;]Yes, <b>both ends up with corrosion of the surface.</b> <b>Both involves the same chemical processes,</b> but the speed of the reaction is greater with PVC plasticizers. Plasticizers can draw moisture and act more like an active acid gel to start corrosion. It is also rather distinctive in appearance and draws attention. The beginning of verdigris is more subtle and slower and depends on the moisture and environmental factors against the coins surface by air as well as molecular diffusion of the contaminants. </p><p><br /></p><p>As to whether both can be halted has been often debated. PVC activity has a &quot;pre-corrosion&quot; state where it is &quot;gelling&quot;, and can be removed with acetone. All coins start to react with environmental factors right after they are minted unless they are sealed in a vacuum or solid acrylic. Any container that can be opened can &quot;leak&quot; over a period of time, including slabs or those called tite from air, just much , much&nbsp; slower. Patina actually protects the coins from quick chemical reaction, but with PVC, it&nbsp; progresses to corrosion faster. Moisture is the key. If moisture is greatly limited by using moisture removing chemicals, or sealing in zip lock bags, or sealing in mylar flips, the process is stopped or at least slowed down beyond our normal lives. In dry environments, with little corrosive substances in the air, corrosion can take hundreds or thousands of years. </p><p><br /></p><p>Toning is a stage where the corrosion is in such thin molecular films that they refract the light to produce coloration different from the initial metal color. Differing thicness of corrosion film produces difference diffraction colors. Such patterns may be in colors and display that they are either &quot;pretty&quot; or &quot;ugly&quot; depending on the observer and their reaction. Toning can be fast or very slow, but the chemical processes are the same whether done by nature or aided by humans intentionally. Once the tone is obtained, protection must be done or the corrosive process may continue slowly and the tone changed.</p><p><br /></p><p>Some have differing thoughts on the above, so it is &quot;IMO&quot; , but chemistry is chemistry.</p><p><br /></p><p>Jim[/QUOTE]</p><p><br /></p>

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