The most effective way to clear a blockage is to thin out the mucus. When mucus is thin and watery, it drains easily; when it is thick and dry, it sticks to the sinus walls and creates pressure.
Try acupressure. Firmly pressing the bridge of your nose or the area just above your eyebrows for several seconds can sometimes provide a momentary "opening" sensation. Over-the-Counter Solutions how to unclog sinuses