Using a steam grout cleaner
If you need to clean tile grout, avoid chemicals like bleach. The best solution for having clean joints is to use a steam cleaner. This is a simple method. The high heat of the device helps eliminate limescale, dissolve stubborn deposits and prevent the formation of mold.

Fill the steam cleaner with water and attach a brush. Run the steam cleaner over each joint using rubbing movements. Repeat the operation several times until you obtain sparkling joints.

Steam grout cleaners are available at department stores, hardware stores and online stores.