To remove limescale or rust stains, add an appropriate amount of white vinegar or baking soda for the stainless steel variant/neutral dishwashing detergent for Tritan variant and dilute it with warm water. Use a soft cloth to clean it thoroughly. Rinse with water and then dry it off or let it air dry. Avoid using hard objects to scrape off limescale or rust stains as it may damage the interior of the bottle.