Hi Joan, I just got out my old college text “Biological Techniques –
Collecting, Preserving and Illustrating Plants and Animals” and read the
chapter on Mollusks.  The author, Jens Knudsen, tried many different
techniques to kill and relax mollusks but all varied in their success.

Here are some of the methods mentioned:  1). Marine clams may be killed by
soaking in fresh water (you tried this method without success); 2). Place
bivalves in habitat water until they open up (they suffocate or die of the
heat); 3). Heat-kill method -- hot water, boiling water, microwaving; 4).
Freeze-kill method; 5) various necrotizing agents added to the water -Epson
salts (You tried this), alcohol (you tried this), menthol, benzocain, etc.

After the kill step the author suggests putting a wooden peg (3/16th inch in
diameter) between the shells and then sequentially preserving in 35%, then
50% and lastly 75% alcohol.  Formalin at 5% and then 10% can also be used
but not much of this chemical is used any more.

My suggestion is to give them some hot water and see if that does the trick.
I had some obstinate oyster shells that I both planned to eat and keep the
shells from and I used the microwave at 5-10 second intervals and it did the
trick.  The only problem with this method is its trial and error.  Too much
time and you can blow up the shell or the animal and make a terrible mess.
I've heard of people having to buy a new microwave oven when they tried this
method with a dead shellfish.

Clams are "tough guys"; maybe they just need a bit more time.  You will get
them eventually.  Bert Bartleson in foggy Olympia, WA
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From: Conchologists List [mailto:[log in to unmask]] On Behalf Of
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Sent: Tuesday, January 25, 2005 10:47 AM
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Subject: pegging clams--how to

Conch-L subscribers:
For a presentation to a 7th grade class, I had the idea to procure
demonstration specimens from my local seafood market.  They had
"littlenecks" and "cherrystones" from Virginia.  I wanted them relaxed, with
foot extended, before preserving them.  Being a novice to narcotization of
marine bivalves, I consulted various references but have yet to find a
methodology to get them to relax.  They have been in freshwater with some
ethanol added for 24 hrs.  Four hrs ago, I took one of those and put it in a
separate container, saturating the freshwater+ethanol with epsom salts, and
placed this container on my office heat register which I have turned up to
at least the high 70s.  Still closed up tight.
Any advice greatly appreciated.
Joan Jass
Milwaukee Public Museum
Email [log in to unmask]

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