Storing coins

I am advising a private collector here in Japan in regards to his
collection storage.  He has a large and important collection of
coins, which are stored in clear poly(vinyl chloride) envelopes.
They are about 1" wide by 3" long and split in the middle so that
the coin can be put in one half and the label in the other half. Can
anyone recommend an archival replacement for these vinyl chloride
envelopes?  What is the best method for storing coins?

Tom Chase

                                  ***
                  Conservation DistList Instance 13:28
                 Distributed: Tuesday, November 2, 1999
                       Message Id: cdl-13-28-017
                                  ***