Re: Rusty Tub
Try removing the overflow, then clean off the rust with oxalic acid. When it's clean, treat the area with a rust converter ( a preparation that usually contains a phosphoric acid solution and other compounds; turns rust into a black iron phosphate finish, which can't oxidize any more.), then spray a bit of rustoleum paint on the hidden part for good measure. IOW, don't spray anything that's not covered by the overflow plate. It may be worth a try .
A magnet sticks to cast iron, too.
Remove not the ancient landmark, which your fathers have set.