I have quite a large area of ceramic tiles and I clean it with bleach and water and they come out great! I even have a medium brown colored grout and it doesnt affect the color at all. I do that sometimes, and also do all my floors with my Eureka Delux Steam Cleaner for floors, much quicker and easier

. I have had it forever...great machine.
P.S. Alittle off topic, but would like to suggest for any other type flooring is Don Aslett Cleaning Secrets Floor Restore. Everytime I do them, people think they are brand new floors! I never tried it on the ceramic tiles, but since I have the wonderful chore of doing all my floors tomorrow, I will try a small spot and let you all know how it works.