If you have white tile grout that looks dingy, especially in bathrooms or kitchen areas, then you will be relieved to find out that you can get your grout sparkling again with simple, non-toxic household items.
Mix 1/2 cup of baking soda with 1/4 cup of white vinegar to form a paste.
Apply paste to dirty grout areas (depending on how large the grouted area is that needs to be cleaned, you might need to make more paste). Let it sit for 20 to 30 minutes.
After the paste has penetrated, use the toothbrush or grout brush and scrub the areas that you applied the paste to.
Rinse with a clean sponge and warm water. If a particularly stubborn spot remains after rinsing, simply repeat the process and let the paste penetrate a bit longer, scrub and rinse.