Conservation Showcase: Chinese Yunnan S $1

Posted on 12/27/2010

A recent example from our conservation laboratory.

NCS Conservation Showcase NCS Conservation Showcase
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NCS Conservation Showcase NCS Conservation Showcase

As the popularity of the Chinese coin series rises, an increasing number of silver coins have been submitted to NCS to have a particular kind of corrosion removed. Large silver coins are often submitted with large raised bright green encrustations often accompanied by thick reddish brown to black residues. Many of these coins were buried during times of war when these pieces were used as money. Most likely this type of residue and corrosion is indicative of that.

This Silver Dollar issued in Yunnan Province, undated though issued in 1908, was submitted to NCS to have the raised green spots removed from the surface. Removal of these spots often involves removing both the encrustation and any general residues. Careful removal of the spots was performed while retaining the natural looking surface of this lightly circulated coin.

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