Using this eyelashes and eyebrows repair liquid is easy. First, clean your face and make sure your lashes and brows are dry. Then, use the included mascara - like applicator to gently apply the liquid to your eyelashes and eyebrows. Apply it evenly along the roots for best results. As for precautions, avoid getting the liquid into your eyes. If it does, rinse thoroughly with water. To maintain the effectiveness of the product, store it in a cool and dry place away from direct sunlight. This will help keep the repair liquid in good condition and ready for use whenever you need it.