One day I asked a Local Scholar of my area's mosque that, while performing the masa in wuzu, is it sufficient if I do the masa only on my hair and water does not reach skin, to which he then looked at my hair and said that there is no need for water to reach skin and i can do masa on hair only itslef. Now, my question is that, If I apply gel or oil or wax to my hair, then can I perform masa on that hair? or do i need to wash the hair and make it dry again and do masa? Please give reason also.

If any think obstacle to reach water to hair , must remove it then do masa