Being able to lighten grout colors is a fast, effective way to improve the look of any area by bringing the grout lines back, or close, to their original color. This is a very easy project that will require a small amount of time, but be aware that certain safety precautions need to be taken because the bleaching compound can be harmful to your skin.
Step 1: Clean the Grout
Use a strong tile cleaner and clean all of the grout lines. Be sure to use a clean rag and scrub the lines out as well as you can. If the area is dirty to start with, be sure to sweep up any large crumbs first with a broom or brush.
Step 2: Prepare
Open any windows that are close to the area that you are working on and get your rubber gloves on. Grout bleachers are very strong chemicals that can be harmful to the skin and lungs. If you are sensitive to smells, also put on a simple painter's mask to deflect some of the fumes.
Step 3: Apply the Grout Bleacher
Apply the grout bleacher with a clean rag, making sure that all of the lines are completely coated. Allow it to dry for the directed time before continuing.
Step 4: Wipe the Area
Use another clean rag to wipe up the dried grout bleach. To not scrub too hard, but you want to get all of the film that was formed off of the floor. Allow to completely dry for at least 24 hours before applying any moisture to it.