Woolite Foam Carpet Cleaner - Sprays out in foam stream so you can spray right on grout line. Let set several minutes, brush, wipe away. Easiest way ever to clean gross grout! Hmm might try this at the new house, don't know if my grout is colored or just gross :/
Add orange peels (or any citrus peel) to a quart of white vinegar in a closed container and let it set for two weeks. Combine citrus/vinegar solution half/half with water and use for cleaning. Works on floors, tile, fixtures, etc. Smells good and is tough on scum! Best of all there are no chemicals.