Preheat oven to 350 degrees F. Wash scallops and dry on paper towels. If large sea scallops are used, cut them in thirds. In a blender or food processor pulverize crackers to a fine powder. Empty onto a plate and stir in pinches of salt, pepper, and allspice. With a spoon or the fingers, knead minced onion, leek or scallion, garlic, and lemon juice into the butter. Roll scallops in powdered crackers until thoroughly coated. Shake off excess and place scallops in a casserole. Dot with the prepared butter and add sherry. Place in oven and bake just until tender, 15-20 minutes. Whisk under broiler about half a minute to lightly brown scallop tops. Serve with lemon wedges.