The dirty grouts makes the tiles ugly. I have tried to use the acid based cleaners on the tiles, dirty grouts were cleaned but the polish of the tiles faded after using couple of times. I have tried using detergent soap and also lime juice which were not effective. I am looking for good tricks to clean the floor and walls grouts without any acidic solution, concerned on the polish of the tiles. Color of the tile is white and similar to below image.