When buying whole squid or cuttlefish, make sure that the skin, head, and arms are intact and bright, and they have a pleasant sea smell.
Hold the squid or cuttlefish in one hand, grasp the tentacles with the other, and pull the body out from the tube. Trim the head below the “beak” and discard. Gently cut away and reserve the mercury-colored ink sac behind the eyes. Remove the transparent quill from the tube and discard. Run a finger through the tube and remove any gelatinous substance. Gently wash in a bowl of water. Rub away the light, purplish membrane on the outside of the tube with a kitchen cloth. Remove the “wings” on the head and reserve. Cut the tube and tentacles as desired.