I would like to know the correct way to wipe ones head when performing wudhu? Does one have to reach the scalp? And what if one has hair cream or gel on his hair?

The wiping of the head in Wudhu: The front quarter of the head should be wiped with the moisture remaining on the hand from wiping your arms. You then wipe from the uppoer part of your head downwards towards the face with the length ofone finger. Wiping can also be done with one finger only; although Mustahab to use all three fingers. Moisture however should reach the scalp, and your hand must not reach your forehead.