Message:

<p>[QUOTE=&quot;physics-fan3.14, post: 2487481, member: 19165&quot;]In widely accepted numismatic parlance, &quot;skin&quot; refers to toning or patina, which are natural reactions of the coin with its environment. The compounds formed are oxides or sulfides of the coin metal.</p><p><br /></p><p>Acetone WILL NOT remove these. Acetone WILL NOT affect toning, if it is natural. Acetone will only remove organic compounds. Acetone WILL NOT affect metal comounds.</p><p><br /></p><p><br /></p><p><br /></p><p>There is absolutely no need to treat the coin with kid gloves. Put the entire coin in a glass of acetone, and leave it there. Remove all of the organic compounds from the surface to help in conserving the coin. If the toning, or any other colors were removed then they were not natural toning and shouldn&#039;t have been there in the first place.</p><p><br /></p><p><br /></p><p><br /></p><p>I&#039;m not sure where you got this from. Do you have a reference explaining this? I, and many others I know, have used &quot;skin&quot; to refer to any natural patina on any coin.</p><p><br /></p><p><br /></p><p><br /></p><p>I don&#039;t understand why this would be the case. Natural toning on gold is a compound of silver and copper sulfides - and should be unaffected by acetone. If the color changed by application of acetone, then the compounds on the surface were organic in nature, and shouldn&#039;t have been there in the first place. Do you have pictures, or some sort of explanation for this claim?</p><p><br /></p><p><br /></p><p><br /></p><p>Water will not chemically affect the surface of the coin (unless there are solvents present). If water affects the coin, the substance shouldn&#039;t have been there in the first place. There is a big difference between natural oxidation, and reaction between sulfur compounds in the environment, and surface contamination from foreign materials.</p><p><br /></p><p><br /></p><p><br /></p><p>There is a huge difference between conservation and doctoring. The semantics are beyond the discussion of this post (although other posts have dissected the issue). True conservation seeks to stabilize the coin and remove damaging substances. If a surface is impaired after conservation, it was because the contaminants had damaged the coin already. Doctoring, however, seeks to alter the surface of the coin to improve the apparent appearance of the coin.</p><p><br /></p><p><br /></p><p><br /></p><p>Using acetone on the spot will not produce this effect, if done properly.</p><p><br /></p><p><br /></p><p><br /></p><p>Dipping is doctoring. Dipping removes metallic compounds from the surface of the coin. Sometimes, a silver solute is required to remove the compounds (and, a properly performed dip is still considered market accepable). However, dipping is doctoring. Acetone does not change the metallic structure of the surface of the coin, and thus is not considered doctoring - it can only remove organic compounds.</p><p><br /></p><p><br /></p><p><br /></p><p>Doctoring IS NOT conservation. The two are significantly and fundamentally different processes. There have been many threads on the subject, and a full discussion is beyond the scope of this thread.</p><p><br /></p><p><br /></p><p><br /></p><p>Without closer examination, I&#039;m not sure what caused the mark. If it is a planchet flaw, then acetone won&#039;t remove it (of course). However, treating the entire coin in acetone will cause no adverse effects to the coin (if properly done), and will raise absolutely zero alarms.[/QUOTE]</p><p><br /></p>

Your name or email address:

Do you already have an account?

• No, create an account now.
• Yes, my password is:
• Forgot your password?

Stay logged in