I use Comet to clean my bathroom floors. Comet, Ajax, Bon Ami--it doesn't really matter, although I am curiously drawn to Comet's neon-green packaging. My theory is that there is a point at which Gaudy is so over the top, it becomes sort of mesmerizing. Anyway.
Before we moved into our condo, we mostly had vinyl flooring in the bathroom; occasionally we had ceramic tile. Both were blessedly easy to clean. I was partial to Spic-n-Span, which seemed to do the job just fine. But when we moved to the condo, I had the opportunity to choose my flooring, and for the guest bath I threw caution and common sense to the wind and chose marble tile. It seemed nothing was "safe" for cleaning marble tile, except special marble-floor cleaner, which I used to dubious effect.
Maybe the problem was that we were forced to put the cat box in the guest bath; in the past, we had a basement or an out-of-the-way place to put the box, and when we rented houses, the cat would mostly go outside anyway. But in the condo, the marble floors seemed to absorb the dust from the litter. Using the special marble cleaner, the grout was always disgusting, too. And I didn't have much better luck with the floor in master bath, which is composed of teeny-tiny ceramic tiles, for that 80's gym look. In the case of the master bathroom, the 2" x 2" tile made for a lot of grout that was perpetually dingy.
Completely at a loss, one day I sprinkled Comet on the marble floor in a pique of frustration. I took a brush and scrubbed at a spot and the result was near-miraculous; it was clean. The grout was gratifyingly grime-free, too. I sprinkled with abandon and scrubbed the whole floor. As far as I was concerned, I'd found the holy grail of marble floor-cleaning.
I used the Comet-and-scrub brush technique on the grout around the teeny tiny tiles in the master bath, and the result was as white as can be. Eventually, I fine-tuned the procedure: basically I wet the floor with a mop, then sprinkle with Comet and scrub with a brush. Then I rinse the floors--usually twice--to get rid of the gritty residue. Gorgeous, clean floors, and no one is the wiser for my unconventional methods.
Again, appologies to those who subscribe to my posts via email; I accidently clicked "send" before this post was finished, thus explaining the mysterious email you just got without a title. Yow.