Regrouting

The best product I've found is from Home Depot. It's called Zep Tile and grout clean. It smells like butt, but really works.

I do not have white grout, but I have heard of using "blank" that you can find in a Staples or Office Max. This kind of thing happens bottle that we use to errors made by a white veil typewriter. I show my age ..

There are many whitening grout. Alink to one is below:

http://www.thegreathardwarestore.com/Pro ...

Try this magic sponge, I do not use it. Good luck!

Blaech and scouring pad

washing with bleach and a brush