Rinse your hair with Apple Cider along with Rosemary tea. Both of these ingredients are excellent for your dilemma. They also have Citric acid, which is a natural astringent.
When shampooing do not scrub your scalp. Vigorous scrubbing will activate the sebaceous glands. Massage it gently until it reaches a rich lather, and leave it on the scalp for 5 minutes. Rinse well after 5 minutes. Blot excess water from the hair when drying, always keeping in mind that any vigorous action on the scalp will send a signal to the sebaceous glands to work. This goes for combing and brushing as well.