Fill large kettle 1/3 full of clean, fresh coquinas, completely cover with cold water.
Bring to a boil (Coquinas will open up and fill kettle.) Boil 3-5 minutes.
Drain broth into smaller pan.
If potatoes are used, add to broth.
Return to heat (medium).
Add grated carrot and celery.
Season to taste and serve.
Coquinas have a very delicate flavor and are best as a fairly clear broth.
To gather coquinas, make a square or rectangular shadow box, cover bottom with 1/4 inch screening to allow sand and debris to sift through.