Over time the grout between your kitchen-floor tiles will get dirty, but you can clean it without too much effort. If the grout between your floor tiles becomes stained or dirty, you can easily make it look like new again.
Many stains are on the surface of the grout and can be removed with sandpaper.
If sandpaper doesn't work, you may have better results by applying a pencil eraser. Make sure the area is well ventilated, and wear rubber or latex gloves when working with bleach. If bleach doesn't do the job, you may need to remove and replace the grout. Reapply sealer once every two years.