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How to Get Rid of Efflorescence in Grout

Grout is made of cement, which will naturally create a white or gray and powdery residue called efflorescence. Efflorescence occurs when salt residue moves up through the layer of grout to the surface. It tends to happen if the grout was overly wet when mixed and applied, if the surface was too wet or if you used very hard water to clean the grout. Efflorescence can make your grout look dirty and unkempt. Use products that won't damage the grout. Avoid very coarse abrasives such as coarse steel wool or wire bristled brushes, as these will scratch grout. Don’t try to clean the grout if it's less than three days old.

Things You'll Need

  • Goggles
  • Gloves
  • Sulfamic acid
  • Scrubbing brush
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    • 1

      Put goggles and rubber gloves on to protect yourself from the strong acid solution.

    • 2

      Mix sulfamic acid with water according to the manufacturer’s directions.

    • 3

      Apply the acid solution to the grout with a scrubbing brush. The solution will break up the efflorescence so you can scrub it away. Continue until the stain is completely gone. Rinse the grout with water.

    • 4

      Scrub a pumice stone over the efflorescence on the wet grout if you can still see it. The pumice stone is coarse enough to remove the marks but not strong enough to scratch the grout.

    • 5

      Rinse the area with clear water and let it air dry completely.