What to use to remove rust off concrete?
You can use oxalic acid crystals or a cleanser containing oxalic acid to remove rust from concrete. Wet the area and sprinkle the crystals or cleanser liberally. Wet it again and let it sit a few minutes. Then, scrub with a brush and repeat as necessary. Rinse the concrete. If some rust remains, you can use muriatic acid (dilute hydrochloric acid).
