Do you have some grubby looking grout in between your bathroom floor tiles? Don't despair, or resort to super-toxic cleansers or harsh bleach. You could try using oxygen bleach, as I've suggested in the past. Or, try using liquid dish detergent or toothpaste to get the grime out. Simply squeeze either the detergent or toothpaste onto a sponge, and scrub vigorously. Have you tried this method at your home?