There are a few techniques available to know how to remove rust from cast iron. When cast iron is exposed to water, reddish brown rust appears. The rust stains only spread and increase if not removed promptly.
- Use Steel Wool or a Wire Brush. One way to remove rust from cast iron is to scrub it off with steel wool or a wire brush. This is probably the first step you should use to remove rust.
- Apply Mineral Oil. For cast iron rust stains that don’t respond well to scrubbing, apply a small amount of mineral oil. Let the mineral oil soak into the rust stain. Then scrub the rust with the steel wool or wire brush.
- Make a Paste. A paste of lemon juice and borax makes a good homemade rust remover. Add the lemon juice to the borax to make a paste then apply with a scrubbing pad. Wait several minutes while the paste works on the iron stains. Then scrub the area using a scrubbing pad. Another option is to make a paste of lemon juice and table salt.
- Use Naval Jelly. Naval jelly is sold in hardware stores and is an effective rust remover for cast iron. The naval jelly contains phosphoric acid. The acid dissolves the rust stains. Apply the naval jelly, wait a few minutes and then wipe off. Because of the acid it is a good idea to read the instructions on the label to prevent burns.
- Use Rust Removers. Rust removers are sold in home improvement centers and hardware stores. They are extremely effective in removing rust. These products dissolve the rust with the acids they contain such as hydrochloric acid, oxalic acid and phosphoric acid. Use safety measures when using these types of rust removers. Gloves or a face mask may be needed in addition to plenty of ventilation.