Using Chlorine Bleach

• 1). Pour some chlorine bleach into a spray bottle and dilute it with water. Chlorine bleach is too strong to use undiluted, so add approximately five parts water to one part bleach. Do not use chlorine bleach on colored grout, or your grout will become discolored. If you're trying to bleach colored grout, proceed to the “Oxygen Bleach” section.
  
  
• 2). Spray the grout stain gently to cover it with bleach. Scrub the grout, using a bathroom scrubbing brush or toothbrush. Take a 15-minute break.
  
  
• 3). Rinse the grout with water and examine it carefully. If any of the stain remains, mist it with the bleach solution and scrub a second time. Rinse after 15 minutes. If your grout surrounds marble or granite tiles, try not to expose the stone to excessive bleach. Natural stone surfaces are sensitive to chemicals, but they can withstand small amounts of bleach.
  
  

Using Oxygen Bleach

• 1). Mix oxygen bleach powder with hot water inside a spray bottle. Different oxygen bleach manufacturers have different recommendations for water dilution, depending on the formula, so read the label. You can also use an oxygen bleach liquid spray, which comes prediluted. Oxygen bleach is all-natural — it contains hydrogen peroxide — and safe for colored grout as well as white grout.
  
  
• 2). Spray the grout lines wherever stains appear. For grout in floors, you can also pour oxygen bleach directly into the grout lines, since it doesn't have the corrosive, harmful properties of chlorine bleach. Let the liquid solution settle on the stain(s) for 15 minutes.
  
  
• 3). Scrub the stain(s) with a firm-bristled scrubbing brush or firm-bristled toothbrush. Rinse with water and gently dry the grout.