Spray on - Rust Stains Disappear! No scrubbing, mixing or measuring required! Quickly & safely remove rust from concrete, aluminum siding, stucco, plastic, painted surfaces, wood and fiberglass. Powerful, fast-acting, ready-to-use formula will not harm grass or most plants. Eliminate unsightly rust stains on driveways, sidewalks, decks, fences, outdoor furniture and more! Biodegradable. 32 fl. oz.