Apparently the problem may be more extensive.  Dave wrote that
"CDs manufactured before 1989 and after 1991 have not been reported as
suffering the same corrosion." I had a copy of DG 419-780, Bernstein
conducting Harris and Schuman, that bronzed.  It was pressed in 1987
according to the insert and there is no PDO anywhere I could find.  I wrote
DG and they asked for the bronzed copy.  I sent it and it was replaced by
a disc that has no printing on it at all.  Their letter does indicate that
the disc was manufactured in the UK but doesn't state where.  The letter
goes on to state that "As this particular recording is not available
anymore, we cannot send you a new CD from our warehouse.  So the enclosed
CD is an advance copy (therefore without printed label) which got made for
our internal use before the release." Whatever that means, I do have the
replacement and it sounds just fine.  As this disc predates the period
indicated by Dave, and others, I guess we have to pull out all our older
discs.

Peace,
bob stumpf