Octagon Ceramic Tile Best Way To Update Ceramic Tile?

Best way to update ceramic tile? - octagon ceramic tile

In my bathroom, I want to update tiles. There is little rough octagonal White w / black speckles. Grout is also white. I hate it remains dirty. I thought the sand and put a stain and varnish it, but I do not know if this can be done. 2. Possibility is to replace the grout w / black, but I'm back with the white tiles, anyone know if sanding and staining it would work? I thought I would first try would be cheap, because I have a grinder and I can make myself .. I thought I could use the dyes used to dye clothes (possible?) And only polyurthane seal. If I do something else, remove ceramic tile, .. This can be expensive suggestions?