How to clean bathroom grout? Grouts – those invisible lines between tiles – can be the biggest indicator of how well-maintained a bathroom or kitchen is. When they’re clean, they make the space look fresh and tidy. When they’re dirty, they quickly create an impression of neglect (even on the most expensive tiles). They harbor mold, soap scum, grease, and moisture, which can damage the structure of the tiles in the long run. The good news? You can clean them yourself – with ten simple tricks, ranging from the quickest solutions to long-term protection.