Dirty ugly grout a problem on your bathroom tile floor? A quick easy fix for dingy grout lines is with a Grout-Aide marker. The grout marker comes in five basic colors so your decision to choose the right color for your home is easy. All you do is color in the tile grout lines! A great do it yourself project. If marker gets outside the lines, just wipe it off the tile and continue. Quick drying- the tiled floor with a clean fresh look will be ready to use in no time. Each marker covers 175 lineal feet of grout lines however this may vary depending on the width of grout joints.