Crack is usually made by mixing two parts of cocaine with one part baking soda in about 20 ml of water. The solution is then heated gently until white precipitates form. Heating is halted when precipitation stops. The precipitate is filtered and retained. The precipitate may then be washed with water; this procedure is usually omitted in the street product. The product may then be dried for 24 hours under a heat-lamp. Crack is then cut or broken into small 'rocks' weighing a few tenths of a gram