First, a quick reality check. That expensive stain-remover stick you love? It’s probably helpless against rust. Rust is an oxidation stain, not a protein or grease stain, so soap molecules slide right off it. Don’t blame the detergent—blame physics.
You need something that reacts with the iron oxide, not just “lift” it. Think acid, chemical reaction, villain origin story for the stain. We’re going to be smarter than the rust.