We changed out some screws years ago and DH is doing the final ones on the bottom half of the top section. Some screws won't come out no matter what. Other screws need a repair strip of alum. to snug up the screw. We bought the repair material at Harbor Freight. Finally remembered to spray oven cleaner in a few places in the oven. Tomorrow AM I will wipe out. What do you mean"no self cleaning button on the oven". Something about being on your knees cleaning out the oven makes and keeps you humble.