A good natural way to get rid of grease and oil in your hair overnight and to keep the grease and oil out of your hair is to use some Apple Cider Vinegar to wash your hair with.
Apply some Apple Cider Vinegar to your hair and massage it in to help wash out the oily and greasy stuff from your hair.
The Apple Cider Vinegar balances the pH balance on your scalp which can help control excess oil and grease that builds up in your hair.
You should wash your hair first using the regular shampoo or a shampoo formulated for greasy and oily hair and then after that pour some Apple Cider Vinegar onto your hair and massage it into your hair.
Let the Apple Cider Vinegar sit in your hair for 5 minutes or so and then wash the Apple Cider Vinegar out of your hair.
You can also wash your hair using some Dawn Dish Soap to help remove grease and oil from your hair and then follow up with your regular shampoo to remove even more oil and grease.
Using some detangling hair spray on your hair is also another good remedy to keep your hair from going greasy overnight and sleeping with your hair up can help as well.