Conservation Showcase: China Memento S $1

BEFORE CONSERVATION
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AFTER CONSERVATION
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The heavy reddish and green corroded residues are a common appearance on large silver coins from China made in the early half of the twentieth century. Such encrustations are unattractive and often damaging to the surfaces underneath them. Coins with this type of active encrustations will not be eligible for NGC certification.

The conservators at NCS have developed techniques to help remove these kinds of thick hardened residues. While there is usually some effect of the encrustation on the surface underneath, some coins, such as this particular Chinese Memento Dollar produced in 1927, though lacking a date, can be conserved relatively free of damage. This coin was able to grade numerically with NGC following the conservation.