Moisturizing Your Skin. 1  1. Apply unscented moisturizers to your skin each day to help fight plaque psoriasis. 2  2. Apply olive oil to your affected areas. 3  3. Try applying fish oil to keep your skin moisturized.  4. Try paraffin oils or emulsifying ointment 1  BP. 5. Remember to use mild soaps to keep your skin from getting dry and irritated.