Here are some great methods for getting your grout clean using both organic and other products.
Try a pencil eraser. This household trick is great for cleaning small sections of stained grout. Simply run the eraser of a number 2 pencil over the stain until it is gone. Use a clean white or pink eraser.
Use baking soda. Most dirty grout can be brightened using this natural method.
Make a paste with baking soda and water.
Apply it to the dirty grout using an old toothbrush. Scrub the paste into the grout well.
Wash the grout with warm water when you are finished.
For the tougher stains, allow the paste to sit for a few minutes before you start scrubbing.
Remove tougher stains with bleach. If natural methods don’t work, try a bleach solution.
Put on a pair of rubber gloves to protect your hands.
Mix a 75/25 solution of bleach and water if your grout is white. If the grout is colored, you will have to use plain water. Do not use bleach on colored grout as it may remove the coloring.
Use a toothbrush or the edge of a sponge to clean the grout with the solution. Take care not to get the bleach solution on the tiles.
Rinse the floor with warm water after you are done to remove all traces of bleach.
After the floor is completely dry, carefully apply a coat of grout sealer to the grout between the tiles, to prevent it from absorbing dirt in the future.