After cutting the old floor out, the bonding areas were cleaned up with a grinder. The spot welds left raised areas, those were ground away, along with as much rusty metal as possible.

So unless you cut that out and fab in a new piece, it's very difficult to entirely remove the rust. A lot of times it comes back. - [Alex] So if you haven't figured it out, I'm starting to hate rust.

You can also remove rust from metal with a store-bought chemical rust removers like Metal Glo. It’s formulated for safe use on knives, silverware, cookware , and even jewelry.