The answer to 'bathroom stain removal' is to first identify the type of stain, then use the appropriate cleaning method. Common bathroom stains include hard water deposits, mold, mildew, soap scum, and rust. For hard water stains, try vinegar or a commercial lime scale remover. Mold and mildew can be cleaned with a bleach solution or mold-killing spray. Soap scum can be removed with a mild abrasive cleaner or baking soda and vinegar. Rust stains may require an oxalic acid-based cleaner or a pumice stone.
If the stains are persistent or widespread, it's best to call in a professional cleaning service. They have the right tools, products, and expertise to safely and effectively remove stubborn bathroom stains.