Here are the directions for using Santeen 0200-6-XCP6 Sulfuric Acid Drain Opener: Preparation: Ensure the area is well-ventilated. Wear protective gloves and eyewear. Application: Remove any standing water from the drain. Slowly pour 16 ounces (half a bottle) directly into the drain. Wait Time: Allow the product to sit for 15 minutes. Flush: Flush the drain with cold water for several minutes. Repeat if Necessary: For stubborn clogs, a second application may be required. Safety Precautions: Do not use a plunger after applying the product. Avoid contact with skin and eyes. Keep out of reach of children and pets.