Thanks! I've read that. When I mopped yesterday, I used a 50/50 solution of hot water and white vinegar. I tried cleaning my grout with a water/baking soda paste (waited 15 minutes, then used a grout brush to scrub it off) to no avail. The Magic Eraser worked a lot better. However, I did use baking soda that had been in my fridge, so I'm going to buy a fresh box today and see if that does any better.