Combine the bread crumbs and cracker crumbs, stir in the melted butter. Place a thin layer of the crumb mixture in the bottom of the prepared baking dish. Layer half the oysters over the crumbs and sprinkle with salt and pepper to taste. Pour 2 tablespoons oyster liquid and 1 tablespoon milk over the top. Repeat, layering remaining oysters in baking dish. Season as before with salt and black pepper, if desired. Pour remaining 2 tablespoons oyster liquid and 1 tablespoon milk over oysters; then cover the top layer of oysters with the remaining crumb mixture.