Cleaning grout lines between tiles is a tedious job. Here are a few cleaning options that could make the end result a little brighter and a little whiter.
Option 1: Mix a solution of hydrogen peroxide and baking soda to a paste-like consistency. Spread the paste over a section of grout lines. Wait 10-15 minutes and then scrub the grout lines with a small, stiff brush. Continue to apply the paste, wait and scrub until the grout lines are clean. Wipe the remaining residue up with a clean, damp cloth. Finish the process by washing the entire surface with a mild cleaner. Hydrogen peroxide may bleach colored grouts. Test a small area before using this method.
Option 2: Fill a bucket with 7 cups warm water, 1/3 cup ammonia and 1/4 cup white vinegar. Stir in 1/2 cup of baking soda. Once the baking soda has dissolved completely, pour the mixture into a spray bottle. Spray a small area of grout and wait 5-10 minutes. Scrub vigorously with a stiff bristle brush. Use a clean, damp cloth to wipe away residue. Rinse with clean water. Finish the process by washing the entire surface with a mild cleaner. Vinegar is an acid and should not be used on limestone, marble or travertine tile.
Option 3: Mix equal parts of warm water and a powdered oxygen-based bleach, such as OxiClean. Apply mixture liberally to a section of grout. Allow the solution to work for 20-30 minutes or longer for tough stains. Scrub a stiff bristle brush and use a clean, damp cloth to wipe away the residue. Keep working until all the grout is clean. Finish the job by washing the entire area with a mild cleaner.
Option 4: For small stains, try erasing the stain with a standard pencil eraser or use toothpaste and a toothbrush to scrub the area clean.
Option 5: By far the easiest and possibly the most effective option is to use a Clorox Bleach Pen to coat the grout lines completely. Allow the cleaner to set over night. When you return in the morning, all that will remain is a white, powdery residue. Brush away the residue and clean the area with clear, warm water. Using bleach on colored grout may change the color of the grout. Test a small area before using this method.