Hi Nancy,
There was a rather in-depth discussion of this not long ago. I wish the
conch-L archives were easier to search. In brief, Bynes's disease is not an
"infection", and bleach won't "cure" it. It does not pass from one shell to
another. It is a chemical reaction between the calcium carbonate of the
shell and acid vapors in the air. The "symptom" is a layer of fine white
powder on the surface of the shell. It can affect all shells, but is most
noticeable on those with a glossy finish like cowries and olives (you
probably won't notice a thin layer of white powder on a Buccinum). It can be
prevented by avoiding sources of acid vapors (such as certain woods and
papers), and keeping the collection in a dry place. Moisture is also
necessary to make this reaction take place.
Regards,
Paul M.