HOW TO DO IT:
Put about 100 ml of oil into a shallow bowl. Sit with a towel wrapped around your shoulders. Don't wear anything which might be ruined by oil spots. Brush your hair through and then part your hair carefully with a comb or brush. Dip your fingers into the oil and use your finger tips to carefully massage the oil into your scalp. Cover your entire scalp this way, paying particular attention to hard to reach areas like the back of your neck.
When hair and scalp are both well covered with oil, wrap the towel around your head so as to keep your head warm. Now spend half an hour or so relaxing while the olive oil does its work. When you are ready, unwrap your hair and wash it carefully with your favourite environmentally-friendly hair shampoo.
When your hair is dry you will find that it is soft and silky and easy to manage. If you find that your hair is at all greasy after using olive oil, use less next time and maybe try a shampoo for greasy hair. I've used olive oil for hair over number of years and not found it to create greasiness.