Unrust Rust Remover 16 ounces of dry Unrust Rust Remover makes 2-4 gallons when mixed with water. This is a Great size to do small jobs, with Big results. If you are looking to try us out, this is the Best way. Removes Rust from concrete, fencing, stucco, tools, carpet, bathtubs, and car parts, too many applications to list them all. Safe and easy to use. Will not harm grass or plant material.