While vinegar can be effective in removing mold from grout, it is important to note that it is also acidic and can potentially damage the grout if not used properly. A diluted solution of one part vinegar and two parts water should be sufficient for general cleaning, but if you are dealing with a more serious case of mold, you may want to use a stronger solution of equal parts vinegar and water. It is important to note that using too much vinegar can cause the grout to become discolored or even crack. Therefore, it is important to only use enough vinegar to remove the mold and never leave it on the grout for extended periods of time. After using vinegar, be sure to rinse the grout with plenty of clean water and then dry it with a soft cloth.