All this talk about bleach and acid on these gems of the land and seas
gives me the heebie-jeebies!!  I have seen the effectiveness of mineral oil
and was quite impressed.  Just food for thought, we don't know what these
harsh chemicals are actually doing to the integrity of the shell, i.e.
crystaline structure, microsculpture.  Future museum staff and researchers
may be muttering oaths not fit for the internet if these collections end up
in their hands someday.  I can only suggest that we all try to use the most
benign cleaning agents we can find. Ok, I feel better.  I'm off my soapbox
now.
Kurt