Thanks for the info above. I know I need to do this so badly!! I will check out that Marblelife stuff and see what they say about it.
The thing is, I have used those disposable Clorox wipes to clean up spots here or there, and sometimes on the grout if the dirt got on it. It did clean it, but the thing is, those spots are now lighter than the rest of the tile which I assume is dirty. I don't like that!!
Any other tips or advice?