Recovering bleached Cypraea

Original Forum Question : I rencently accidentally sink 2 Cypreae with other shells in bleach and they came out terribly awful, their nice shiny surface turned into a chalky white color… Any idea on how to recover (at least a bit) of their original aspect?

I think it's really too late and I never eard of any solution to recover the natural glossy appearence of cowries (and other naturally polished shells)…
(Answer by Touitou David via the Forum)