I'm looking for a solution to return old and dirty grout back to new again. I've heard of water based formulas that quickly bond to grout lines to create an even and uniform color and appearance while locking out future stains. I've seen them in assorted colors which will bring grout to a uniform appearance
and protect new grout from discoloration and reduce maintenance. Does such a creature actually exist?

I tried using something called Grout Cover Seal manufactured by Tile Solutions. It comes with a wheel-like applicator that fits into the grout lines. The solution is like that of white-out. While it looked good initially, it began to chip as soon as I started cleaning the tile.

Would staining 50 year grout be wise?

I've scrubbed and scrubbed and know the tiles and grout are clean, however, I want them to look clean and uniform.

These forums are the best !!!!!!!!!

The existing grout cannot have a sealer on it or the colorant will not bond.

One brand to look at is at www.groutdye.com. Another is made by AquaMix.There are others, but I cant remember their names, one is something like "This Old grout".