I have a job in which there is previously installed but not grout release sealed BLUESTONE Tiles. I must remove all the soil on the tiles and whatever material that the tradesman have spilled or spattered on the tiles. What would be the best method/system to remove these stains that have penetrated into these unsealed tiles? In addition I have to apply a sealer enhancer and have not been able to determine the proper amount of time in between applying the sealer and wiping it off. Is it 1 minute, 2 minutes or longer? How many hours or days between second applications of sealer?