The process of removing shower tile mildew may require a great deal of work on your part. Start out by using a nylon scrubbing brush to scrub as much of the mildew has you can off of the tile and grout. Next, use regular white vinegar and paper towels to clean off the tile. This should help you remove any excess mildew or hard water stains that are on the tile and grout. Keep in mind it is easier to prevent mildew than to remove, so take care to regularly clean your shower walls.