I now have beautifully clean grout again! My main bath has pale blue floor tiles with white grout. Looked beautiful when first installed (25 yrs ago), but has been a hassle cleaning the grout ever since. I tried so many things but it never came completely clean. Recently, I found 2 different tips for cleaning white grout, #1 said to use an oxygen cleaner with water solution, sponge on liberally and let it sit for 15 min, then scrub with a brush, rinse and let dry. #2 was to use a magic eraser to scrub the grout. I used a combination of the 2, first the oxygen cleaner, followed by a good scrubbing with the brush, then scrub with the magic eraser and rinse with clean water. Yes, it took a fair amount of elbow grease, but lo and behold, my beautiful white grout is back! After 25 yrs, I finally found something that works! I'll give it a couple of days to dry really well, and then seal it. Never again will I use white grout, but at least I've finally found a way to get it clean.