The best way to ensure your scallops are grit free is to buy diver scallops—which are also more environmentally friendly. Most sea scallops are fished by dragging heavy nets across the ocean floor—and in the process, the scallop can pick up bits of the sand. Diver scallops are actually harvested by hand (thus the name).
Unfortunately for many home cooks, diver scallops are not as readily available. If you regularly get grit in your scallops, you may want to consider buying them elsewhere. But also, try this method suggested by Anthony Sasso, Chef de Cuisine at New York City's Casa Mono restaurant:
1. Rinse the scallops individually and very quickly under cold water. (Keep the contact brief so the scallops don't absorb the water.)
2. Thoroughly pat scallops dry.
3. Wipe the skillet clean with a dry cloth before cooking to remove any small, hard-to-see particles from the pan surface.
Recipe pictured: Pan-Seared Scallops with Cilantro-Celery Mayonnaise, Cooking Light