rust in the pinch welds around the bottom of the door

[Ontcalimo]

The acid works well. I would then brush it with steel brush, rinse it out and dry it. I would also pour some POR 15 rust paint on it. I bought two doors, and I am planning on filling those areas with short stand fiberglass or por 15 epoxy putty so water does not sip through there and only exit through drain holes. I hope the proactive measure work in long run.