last week my friend cornrowed my hair and used copious amounts of hair grease plus oil because my hair was very dry. today i was redoing some braids and was dismayed at how much grease was on my hands. i have no real idea on how to get my scalp clean. i doubt i know how to properly wash my hair anyway. everytime i wash my hair my scalp always has a white residue. i just wanna know how am i to get my scalp truly clean?