Jim,
 
Try freezing, then a quick bit in a microwave, then bleach, soap and water, and
finally silicone.  Remember, this comes from a landlocked collector who gets
the vast majority of his shells from dealers (and in the last year some trades
from some great Conch-Lers).  But I have used this method for the few shells I
have personally collected and (minus the freezing and the microwave) for shells
I occasionaly get that I think need more cleaning and it worked fine.  It is a
bit messier than pulling a cooked animal out but it will work.  By the way,
there is a special bar of soap made for artists to clean the hands of
painters.  It can be found in most paint/artist/hobby stores and is a dull,
muddy green in color.  I use this stuff by loading some on a wet toothbrush and
then scubbing the shell after the bleach bath.  It works wonders.
 
Tom Eichhorst in New Mexico,USA
 
Jim Miller wrote:
 
> Once again I am turning to you folks who are much more knowledgeable than I
> for information. What's the best way to preserve the color in specimens of
> Polinices (Neverita?) duplicata? After boiling and removing the animal, my
> shells take on a mottled, cloudy, hazy quality. All the deep olive, pale
> tan and blue gray color seems to vanish in a milky mess. I have one old
> specimen that I collected in the 1970s and it doesn't have this
> discoloration, though it was cleaned the same way (boiling). Yes, I let the
> shell cool down before removing the critter -- I thought I might be taking
> it out of the soup too soon, but the next one looks exactly the same and it
> was very cool before I cleaned it.
>
> Help anyone??
>
> Thanks in advance,
> Jim Miller
> Tallahassee, Florida