Take a lemon and squeeze until you get about 2 tablespoons juice, pour into the head, flatten and knead up to the scalp. After that, grab a glass of water mixed with 1 tablespoon of lemon, pour back into your hair, wait a few minutes then rinse with water. Repeat several times until your dandruff is completely gone.
By using coconut milk
Mix the coconut milk from half a coconut, one glass of pineapple juice, lime juice, and a half a glass of coconut water. Stir evenly. Use this mixture to wash your hair once every five days. Clean with shampoo each time.
Source: http://tips-tips-ampuh.blogspot.com/2012/05/tips-menghilangkan-ketombe-secara-alami.html