If the grout is permanently stained, will I need to clean out the old grout and put in new? These are small 1" tiles. Fortunately it's only a small area that needs cleaning.
I have seen grout cleaners or bleachers in the stores, but I don't know if they'd be able to clean this type of stain. Since this is under the toilet tank, I'd almost be willing to put something on there that would color the grout back to white, since it'll be a non-traffic area, and somewhat obscured (indirect lighting).
-= N =-