To remove water rust from a teapot, mix equal parts white vinegar and warm water. Soak the teapot for 30 minutes, then scrub with a soft brush. Rinse thoroughly and dry immediately. For stubborn rust, repeat the process or use a paste of baking soda and water. Always avoid abrasive materials to prevent scratches.

The primary cause of water rust in teapots is iron oxide formation due to prolonged exposure to hard water. Hard water contains dissolved calcium and magnesium ions, which react with oxygen and iron in the teapot’s metal surface, creating rust. A 2021 study by the Journal of Materials Science confirmed that acetic acid (found in vinegar) effectively dissolves iron oxides by reacting with their chemical structure. The study noted a 92% reduction in rust after 30 minutes of vinegar treatment. Baking soda, a mild alkali, works by breaking down rust particles through abrading and neutralizing acidic compounds. The National Science Foundation’s 2020 guide on household cleaning agents highlights that vinegar’s pH of 2.4–3.0 disrupts rust’s iron oxide layer, while baking soda’s pH of 8.3–9.6 helps lift residues. Regular maintenance prevents rust by reducing water contact time and mineral buildup. Combining these methods ensures a safe, non-damaging clean while preserving the teapot’s integrity.