Harpic Oxi Action BlEach Crystals are best on tough stains. Kills germs on contact. Powerful foaming action. Oxygen action. Dissolves tough stains. Suitable for septics. Hospital grade disinfectant. Directions for use: 1. Flush the toilet 2. Sprinkle Harpic BlEach Crystals with OxiAction around bowl sides and into the water. Allow to foam. 3. Leave Harpic BlEach Crystals with OxiAction for at least 10 minutes or overnight if possible to allow its powerful germ killing and cleaning actin to work best. Brush thoroughly then flush away. Harpic Oxi Action BlEach Crystals are best on tough stains. Kills germs on contact. Powerful foaming action. Dissolves tough stains. Hospital grade disinfectant.