No need to keep them all, but...
SPOILER
-
-
-
-
-
- You can take one or two and bring them to Taerum Fuiruim (sp?) in Beregost, heŽll make you an armor if you choose the correct dialogue. Anyway, you should have only 1 angkheg shell when you talk to him, drop the others first, then repeat the proccess to make more.
------------------
"Sigh" -Ertai, Captive of the Blinding Angel