I noticed some rust forming on my canopy hinges so I made a plan today to replace them. Two hinges removed and replaced with no problem but the third hinge has a lot more rust damage than I had realized. I can't get the phillips screwdriver head into the screw. I've tried to loosen it up with WD40 and some elbow grease but its not working. Anybody have any ideas on how I can get these screws out?