Shake well before use. Holding approximately 10cm from the hair carefully spray mousse evenly over dry hair, so that the scalp and hair are fully covered. Work into the hair, spreading the mousse thoroughly and evenly from the roots to tips. Ensure mousse is left in the hair for at least 8 hours (It can be left in overnight if you prefer). Rinse or shampoo solution out (you will notice it comes out easily, with the dead lice). Apply again after 7 days to combat any lice which may hatch in that time.