Can anyone tell me what the small dots of white powder that sometimes
are found on the backs of (usually gummed?) stamps in old albums might
be? I am working with a vintage 1950 album and occasionally encounter
these--like tiny puffs of confectioner's sugar.. Can I just brush the
powder off and mount the stamps (I use Showguard mounts for almost
everything) or do they have to be cleaned in some special way to avoid
damage to themselves and to nearby stamps in my new album? The most
recent ones were on acid-paper Transcaucasian Republics stamps but I
also found them on some non-acidic-paper Chile stamps from the 1940s.
There's no sign of powder on the album pages around the stamps--the
powder seems to have formed as some kind of chemical reaction between
the stamps and the album pages. I do not find the powder on the
hinges.

Thanks in advance, Phil Atley