Are there any grout experts?

[ChiTownZee]

I'm looking for recommendations for products to clean and then seal grout. Our entire first floor is tiles and the grout is starting to look pretty bad. I noticed yesterday when the sofa was moved how white the grout was under it, now I HAVE to do something. Any hints?

 

[olena]

I've had great success with Zap on white grout.

 

[aahmom1]

Tilex works wonders on grout. Make sure you open the windows though, that stuff kills me.