Put a small amount of the contents of the bottle n.1 in a small clean bowl and close the bottle (any product left over can be used again if the bottles have been well closed immediately after use and stored correctly). Add an equal amount of the shampoo in bottle n.2 (following the same instructions for closure) and mix thoroughly. Apply on clean, dry hair and leave for 15/45 minutes depending on how much you want to lighten your hair. Do not exceed 45 minutes. Massage delicately and rinse off with cool water and dry. If necessary repeat the operation after an interval of at least 1 week.