Do not be afraid of using too much. When you apply the cream or ointment stroke it gently into the skin rather than rubbing vigorously. Also apply in a downward motion that follows the line of the hairs. Emollients by themselves will not clear your psoriasis, but they will make you skin feel more comfortable. Psoriasis can affect the scalp.
Coconut oil is a very effective emollient treatment for the scalp.
Coconut oil is a greasy preparation and is best applied overnight. You may need to ask a relative or friend to help you apply the coconut oil. You will need to part your hair and apply generously by rubbing into the scalp, your hair will be greasy from the oil, so to protect your bedding use an old pillow and pillowcase and you could consider sleeping in a shower cap. The next morning simply wash your hair with a tar shampoo. The Psoriasis Association and the Psoriatic Arthropathy Alliance both provide useful information.