CLR usually works quite well for stuff like this. It’s a spray cleaner. I think it stands for Calcium, Lime, Rust remover.

Yes, and I think, potentially, that it could be so advanced that we don’t have the ability to recognize some or all of them.

I would replace it with something that doesn’t rot, like Hardie Sierra 8. It’s expensive, but if installed correctly it’ll last forever.

It’s very good. Kenji Lopez-Alt swears by it, and if it’s good enough for him, it’s good enough for me lol. I get it at Costco, and I don’t think it was that expensive.

Rao’s

By it’s name, maybe?