This is an interesting picture of the white tile. My first comment would be it looks like something has been spilled on the tile and stained the tile the color of the materials spilled. I would try the following:
1. Clean the tile with a alkaline based cleaner,
2. Vac up the cleaning materials
3. Clean a second time using a neutral cleaner .
Hopefully this would clean up the mess.
If that does not work then use the same process but use an acid based cleaner in place of the alkaline cleaner.
While scrubbing this area you may want to add an mild abrasive to your cleaners. You may find a product like soft scrub will take care of the problem. It’s not likely it penetrated through the glazed finish.
John E. Freitag
The Stone and Tile School
The problem that is happening with the white tiles is that they are staining and discoloring.
Does anyone know what this is or could be.I havent seen this in person yet only seen this pic.Is there a remedy?