How to Clean Mortar Mix Dust off of Brick


Bob asked: How do I clean mortar mix dust off of brick? I installed brick using mortar mix, and the residue was left on and dried. It was an inside wall behind a wood stove. How do I clean the brick back to its natural color?

With the right supplies, it’s actually quite easy to remove mortar from bricks. In fact, this method works whether the mortar has been there for days or years. An important point, because if there’s mortar you do NOT want to remove, take care to protect it from your cleaning efforts.

You Will Need:

  • Muriatic acid (sold locally in paint and hardware stores)
  • Steel scrub brush
  • Eye protection
  • Acid resistant gloves
  • Paint brush
  • Water
  • Bucket

Steps to Remove the Stain:

  1. Before you open the muriatic acid, make sure you have skin and eye protection in place. This is important, the acid will spray as you scrub.
  2. Read label directions before you begin to determine the proper dilution of muriatic acid to water.  If no specifications are given, mix one part acid to one part water. NOTE: Always add acid to water instead of adding water to acid.
  3. Create the proper strength mixture in the bucket.
  4. Use the paint brush to apply the acid mixture to the mortar you wish to remove.
  5. Wait for the fizzing to stop before using the steel scrub brush to clean the mortar off the brick.
  6. Rinse with clean water.
  7. Repeat if necessary.
  8. Properly dispose of acid solution when the job is finished. Do not remove protective wear until the acid has been properly disposed of and/or stored.

Additional Tips and Advice

  • Muriatic acid is a hazardous material. Use extreme caution for proper use, storage and disposal of muriatic acid. See the label for precautions and directions.
  • Avoid scrubbing “between the cracks” of the bricks so you don’t accidentally remove the mortar you want to keep. If precision is key, use a small steel brush for greater accuracy.


  1. Alwyn says:

    What is muriatic acid?

  2. Melanie says:

    Muriatic acid is another name for hydrochloric acid.
    Source: Wikipedia – Hydrochloric acid

  3. Sam says:

    I have bought the face brick, and built my house, and now have to brake down the other room and need to use those bricks again as I took care to remove them, but they have mortar in the holes and on the side. I need to clean off the mortar; need the best solution to use.

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