So to get lasting “better than new” door and window operation begin by removing the window regulator, door latch, inner door handle and outer door handle/push button from the door. Soak the latch and inner door handle mechanism in solvent, the wire brush and blow until clean. Clean all the sliding tracks and pivot points of the regulator. Inspect everything for excess wear and broken parts or springs. Remove the button from the outer door handle and clean the dries grease from the stem. Be sure the end of the stem coming off the button is still round and smooth on the end. Check the contact point where the button stem slides on the lever, sometimes a little polishing is needed.