Help with this moga controller

So I've had this for a while and still works fine except for the right bumper which needs lots of force to work. I've already tried cleaning both he contact on the board as well as the silicone pad with 91% ipa and it always only helps short term. When I blow into the bumper as I've read with people with similar problems on other controllers that helps short term. What other possible way am I missing to make a more permanent fix?