>Roland, I'm not a very expert chemist either, but I think I may help answer
>your question about bleach.  Both hydrogen peroxide and calcium hypochlorite
>are strong oxidizers which is the basis of their bleaching effectiveness.
>The concentration of the product makes a difference too.  Here in the USA
>calcium hypochlorite can be found in concentrations from about 4% up to
>nearly 10%.  Most of us probably use the "standard" 5.25% household bleach
>diluted about 5 to 1 for cleaning shells (about a 1% solution).
>
>The environmental benefits of hydrogen peroxide are probably real since the
>chlorine in the calcium hypochlorite forms some pretty nasty secondary
>products, and some of them are quite persistent in the environment. Bert

Laundry bleach is sodium hypochlorite.

Hydrogen peroxide (H2O2, no subscripts available in Eudora) breaks
down by losing a hydrogen atom, becoming plain ol' water. I have
problems with stored H2O2 breaking down...

Bleach is safe for use full-strength with all shells with low organic
component (ie do NOT use it on pinnids, pteriids, isognomonids); it
will also eat periostracum, so don't bleach shells composed entirely
or nearly so of periostracum... such as many Rhytididae!

H2O2 will attack the organics in ANY shell, dimming colors and
rendering the shells extremely brittle. As I know from experience...

Potassium peroxide (KO2) will attack the shell's carbonate, as I
found when trying to soften fossil matrix.
--
Andrew Grebneff
Dunedin
New Zealand
Fossil preparator
<[log in to unmask]>
Seashell, Macintosh, VW/Toyota van nut

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