Wow, I will admit I was skeptical, however it works really well. I did you use a tile brush after application, so I'm sure that helped. The grout looks so much better and super easy to use.

Does not work at all. It gives off annoying strong bleach smell and that's about that. My grout is not very dark/dirty. But I wanted to get rid of a few darker spots. Well... they are still there. They should provide the information if the grout needs to be sealed otherwise it is not going to work. Or vice versa.

Bought this grout cleaner its cheap and it works really well. Make sure if you are doing a big area you get a few of them.

So this works. I wipe out my shower every day, but along the edges it had gotten dark in the grout. I already had it re-grouted once which was pretty expensive. With this product, you shake it, then put it on, then just leave it. The next day I wiped it out. Stains completely gone. Then I tried it on the grout behind my sink and around my faucets, and the stains were completely gone. Great product. If you had a huge area of stain I don't think this would be great as it is a small amount and more for just edges.

This hasn't really done what I was hoping it would. I wanted to use it on both shower and kitchen tile, and it hasn't done much for either.

Regular old bleach, the thing I normally use, works better and is lots cheaper. The gel aspect of this stuff would seem to mean it should stay in place longer and therefore have more time to bleach a stain, but it doesn't seem to help. I sanitize regularly, so it's not like any discoloration has been there for long, but yet these pens have still provided only minimal improvement.

Regarding the gel aspect, I wonder if I could mix regular bleach with something like flour - not something that would react chemically and be dangerous - in order to make it stay on a vertical surface for a longer time and have more chance to work...