Credit: Getty ImagesBefore Getting StartedWhen cleaning toilet bowl stains, it’s important to consider the type of stain and the materials you're using to clean the bowl. “And then, of course, regular weekly cleaning requires another.”The most common cause of stubborn toilet bowl stains is hard water buildup. “You may also notice toilet stains from simply not flushing enough, if the toilet has been sitting stagnant for a few days,” says Stein. Safety PrecautionsIt’s important to follow some safety precautions while cleaning your toilet bowl. “And ensure you know the material of your toilet before using any products, so as not to damage it.”How To Clean Toilet Bowl StainsBelow, we’ve listed two different methods for how to clean toilet bowl stains.