Butter the insides of a 3 quart. Pan to the top, add the cocoa, sugar and salt mix in milk and place on heat and stir until it comes to a boil. Do not stir after it comes to boil. When it comes to a soft ball stage add oleo and vanilla, let stand till it becomes luke warm. Beat with a spoon until it loses its gloss, spoon out into greased pan. Let cool slightly, cut into serving size.