i tiled my kitchen floor last year used unibond rapid set adhesive and unibond grout both powders. in my own admission i did a good job of it. thing is that when i grouted, i like a divvy, didn't seal the grout, so all the grout is a nice light grey except around the cooker where fat has splashed making the grout dark in places. i have tried cleaning with different things including patio cleaner but to no avail. i think the grout will have to be removed in this area and re-done. how/what do i remove it with and what do i then seal it with. any ideas appreciated. dj.