My parents have a red brick bloor in the dining room of their bicentennial home. It's mostly shiny, so sealed? At some point they had a water leak and now the floor has a lot of white yuck on it. Sherwin Williams recommended using a cordovan shoe polish to renew the red color. It kind of turns the white blackish, though, and doesn't really REMOVE the gunk. I'd like to surprise them by cleaning the floor while they're out. Do you think I could scrub it off with baking soda? Vinegar? Both?

I don't want to make things worse, and they don't like harsh chemicals in the home.
Thanks!
Kate