Designed to remove rust from metal objects. For best results, soak rusty items in Must For Rust. Make sure all oil and grease is removed. Works great on rusty tools, hinges, nuts and bolts. Must for Rust will etch the surface and protect from flash rust. After drying one hour, prime and paint. Water-based. Non-flammable. Biodegradable. 32 ounce trigger sprayer. Krud Kutter/Supreme Chemicals of Georgia.