>I am aware that the individual layers of the shell is also bonded
>together with concholin, so the process should not be too
>aggressive, or it should be easily arrested when the surface layer
>is removed, to avoid dissolving the whole shell.
Laundry bleach (sodium hypochlorite solution) at 100% will do the trick.
--
Andrew Grebneff
Dunedin, New Zealand
64 (3) 473-8863
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Fossil preparator
Seashell, Macintosh & VW/Toyota van nut