Sebum is the oily substance that appears on your skin and scalp. The appearance of sebum is a natural and healthy process, because at the end of the day it helps keep your skin and hair from becoming too dry. It protects the skin against the drying effects of water and wind as well. The real issue is, that in some humans, sebum tends to overproduce, and thus- causing your hair and face to appear greasy and oily. The only real way to properly deal with it is to know how to deal with it when it does appear.
Brushing your hair
Brushing your hair from the scalp to the tip of your hair using a boar-bristle brush before you go ahead and wash your hair .
Know what water temperature your hair best reacts to. Usually, it is best to use warm, instead of hot water showers. Hot water tends to strip your skin, causing your scalp to product even more sebum.
Control how much conditioner your apply
Conditioner is great for your hair, but you gotta know your limits. The recommended amount of times a week you should use conditioner is twice a week. Don't overuse it!
Massage your head when shampooing
Use clarifying shampoo and make sure your massage into into your scalp using your fingertips. Under no circumstances should you use your fingernails, since they may cause scratches on your scalp which would lead to your scalp producing more oil.