Sealing Ceramic Tile Sealing Grout On Ceramic Tile?

Sealing grout on ceramic tile? - sealing ceramic tile

Our sauce is a little white ceramic (mushroom) color. He begins to gray in spots and we want the original color back. We are trying to seal someone to hire or do it yourself. If you are someone who would rent the cheapest place, of course, do a good job? If we we do not, as you are and what is the best product to use? Suggestions would be greatly appreciated.