Storing coins

Does anyone know how to tell if a particular plastic is likely to
outgas acidic components?  I have a museum client who has been
housing Greek and Roman bronze coins in "Archival" plastic sleeves,
similar to photographic slide sleeves; however, the coins are
starting to bloom with bronze disease and I'm suspicious that the
plastic may not actually be suitable for holding bronze coins and
outgassing corrosive reagents. I tried to test the plastic using a
pH pen designed for testing paper, but the results were ambiguous.

Susan White
White Conservation Services


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                  Conservation DistList Instance 23:42
                 Distributed: Wednesday, April 28, 2010
                       Message Id: cdl-23-42-019
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