Try Oxygen Bleach
If you have tile floors, grout is most likely the bane of your existence. You've probably tried everything -- short of getting down there with a toothbrush -- to scrub the grime from your grout. Let us introduce you to your new best friend: powdered oxygen bleach. A little of this nontoxic powder dissolved in water and left to soak on your grout will remove even the toughest stains -- with little to no scrubbing!