Things You'll Need
It is common to see bathroom tile grout stain, and it looks more obvious if the grout color is white. The stains in the bathroom tile are not just from mold and mildew. They also could be due to soap scum, dirt or hard water deposits. Simple cleaning methods help remove the stains and leave the white grout clean.
Spray the grout cleaner on the grout and wait for 10 minutes. There are special grout cleaners that can be used for white grouts. Use the scrub brush, and scrub the grout gently.
Use warm water to clean the grout. This will remove the soap scum, dirt and some of the mildew. Repeat step one and step two if necessary.
Examine the grout closely. The grout might still look greenish-grey. This is probably some mildew that is covered by the hard water deposits and is clearly visible in a white grout.
Pour vinegar just enough to soak the paper towel. Too much vinegar might break the tile grout. Use heavy duty paper towel so that it does not rip when it gets wet.
Spread out the vinegar-drenched paper towels so they cover the floor tile and the vertical tiles. Wet paper towels usually stick to the vertical tile surface, too. Vinegar is acidic, and it works well to dissolve the alkaline water deposit.
Check the paper towel every hour to make sure it is still soaked in vinegar. If it gets dry, then remove the paper towel and use another towel with vinegar. Vinegar is a very mild acid, and it acts slowly on the hard water deposits.
Lift a piece of the paper towel and check if there is an improvement in the grout color or if you see the deposits melting. If so, then it indicates that the tile is ready for the next step. If the grout still looks dirty, then put the paper towel back, and let it sit on the tile for another two hours. It might take up to eight hours or even days to completely remove tough hard water deposit.
Pull the paper towel away from the tile, and gently scrub the deposits. Clean the tile with tap water.