How to Clean and Seal Tile Grout
- 1). Put on protective eyewear and gloves.
- 2). Mix 1 gallon water with 1 cup bleach.
- 3). Dip an old toothbrush into the bleach water and scrub the grout in small circular motions. This will remove both stains and mildew that may have developed. Rinse thoroughly.
- 4). Mix some all-purpose cleaner with water according to product instructions.
- 5). Scrub the tile with the soapy water and a toothbrush, then rinse well.
- 6). Apply a silicone sealant to the grout with a small foam brush. Allow to dry thoroughly before use.
Source...