Conservation Showcase: China 1988 Yuan 40th Bank Anniversary
Posted on 2/4/2013
A recent example from the NCS conservation laboratory.
Proof modern coins seem to be particularly prone to developing hazy residues. This commemorative copper nickel 1988 Yuan from the People’s Republic of China honoring 40 years of the People’s Bank is no exception. A uniform brownish gray haze had developed in the years since its issuance obscuring the original surfaces, cameo effect, and important when it is time to certify, grade.
The technicians at NCS have techniques to deal with safely removing hazes from the surface of modern coins without damaging the delicate mirror beneath leaving unsightly hairline scratches. Careful removal of the residues revealed this modern proof coin to have bright cameo surfaces. This coin was able to grade very well with NGC following the professional removal of the harmful residues.
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