You need to know how to clean mold off tile grout to maintain the health and integrity qualities of your bathroom. Not only are black mold stains in your shower grout unpleasing to look at, but if they are left long enough, the mildew and bacteria can be bad for your health as well. Whether you are using eco-friendly cleaners or abrasive scouring powders, you will need to put some effort into getting your grout looking new again.