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<p>[QUOTE=&quot;Roerbakmix, post: 6483859, member: 100731&quot;]Well done! This was my most recent (chemical) cleaning project:</p><p><br /></p><p>[ATTACH=full]1258877[/ATTACH]Note the depositions of horn silver (silver chloride) mainly on the obverse in the dotted border. The cleaning marks on the two figures (obverse) and the fantastic beast (reverse) are prominently visible.</p><p>[ATTACH=full]1258878[/ATTACH]</p><p>The coin was treated with sodium thiosulphate, which dissolves the silver chlorides. As a positive side effect, it leaves a very thin layer grey layer of Na3[Ag(S2O3)2], which is very similar to the &#039;cabinet toning&#039;. In this specific cleaning, this thin layer fills the microscopic scratches resulting in an overall more appealing coin. It should be noted that this is not the same as repationation (i.e. applying a patina), but merely the side effect of dissolving harmful chlorides. The total process took about 60 seconds.</p><p><br /></p><p>This is a coin that was more difficult to clean, and I&#039;m not 100% happy how it turned out. Both the obverse and reverse once had a thick black patina, that was roughly cleaned by the previous owner, showing sharp demarcations of the underlying silver and the black patina. The coin probably looked rather nice with a complete patina. </p><p>[ATTACH=full]1258888[/ATTACH]</p><p><br /></p><p>I used the same method as outlined above, however, this coin required some mechanical cleaning. I used a stiff brush (non-metal) and small metal tools (similar to OP). Unfortunately, the metal was somewhat brittle and small parts chipped of (see 11 o&#039;clock on obverse), causing a ragged flan. Overall, the coin improved, but I was very unhappy with side effects. </p><p>[ATTACH=full]1258889[/ATTACH][/QUOTE]</p><p><br /></p>

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