Remove thin membrane, arteries, veins, and clotted blood around heart. Separate gall bladder from liver, cutting off any of liver that may have a greenish tinge. Cut fat and membranes from gizzard. Make a gash through thickest part of gizzard, and cut as far as inner lining, being careful not to pierce it. Remove the inner sack and discard. Wash giblets and cook until tender, with neck and tips of wings, putting them in cold water and heating water quickly that some of the flavor may be drawn out into stock, which is to be used for making gravy.