Drain oysters and keep liquor. Pick oysters over for shells and set aside. Crush crackers almost to a fine crumb consistency. Pour in a large bowl. Heat butter, soup, pepper, oysters and their liquor and about a 1/2 soup can of water to a slow boil. Pour over crackers and mix thouroughly. Spoon into a greased 9x13 pan and bake at 350 degrees until lightly browned.