Squeeze a small amount — roughly a pea-sized portion for a spot the size of a coin — onto a fingertip or a clean cotton swab. Spread it evenly over the affected area in a thin layer; the vaseline base will feel greasy and form an occlusive film that keeps the ichthammol in contact with the skin. Because the ointment is dark and stains fabric, cover the spot with a breathable dressing or gauze if it might rub against clothing or bedding. Typical frequency is once or twice a day, but the exact duration depends on why you are using it; many people apply it for a few days until the local discomfort subsides. Wash hands thoroughly after each application. Do not use on large surface areas, open wounds, or near the eyes and lips. If irritation increases or nothing changes after several days, stop and consult a pharmacist or doctor.