The black stuff in clams is sediment or undigested food residue, which is not suitable for eating. It is suggested that clams should be soaked in clear water for one hour before eating, and then pickled with cooking wine to remove the dirt.

The nutritional characteristics of clams are high protein, high trace elements, high iron, high calcium and low fat. Clam is rich in nutrients, including protein, vitamins, carbohydrates, calcium, magnesium, iron, zinc and other essential trace elements.