I know what causes battery terminal corrosion but I've sort of got a dilemma. The long screw that holds the battery in place corroded to a concerning degree. It looked just like the positive terminal on a battery that's corroded. I took it off, cleaned it up and found that it's almost been corroded away. It sort of looks like someone just dropped battery acid on it for the heck of it. Anyway I'll attach a picture of the screw after cleaning, it's just strange. Anyone have any ideas?