Cleaning Marble Mosaic Tiles and Grout
We first stripped away all of the old silicone and proceeded to clean the tile and grout by scrubbing in a dilution of Tile Doctor Remove and Go, which is a strong coatings remover that shifts just about anything but is also safe to use on tile, stone and grout. This did the trick and resulted in what was left of the old sealer being removed and had the added bonus of cleaning the grime away from the Marble tiles.Sealing Marble Mosaic Tiles
The bathroom was allowed to dry out for a period of 2 days so as not to trap any moisture behind the new sealer. Then once dry we applied two coats of Tile Doctor Colour Grow which is a solvent based sealer that reaches deep into the pores of the stone preventing other contaminates from becoming ingrained in the tile. The final step was to applying a new silicone sealant to the joints and as you can see from the pictures the Marble tiles responded very well to the process and the shower now looks much fresher if not a new installation.Source: Expert Marble tile maintenance site