How to Clean Excess Mortar Off a Brick Keystone

Ideally, a brick keystone should be cleaned of excess mortar before the mortar dries. If you've found that a newly installed keystone -- the trapezoid-shaped brick placed in the center of an arch of bricks -- has mortar debris on its surface, treat it according to the brick type. Keystones are often a lighter-colored brick, which can be tricky, because the acids typically used to clean mortar from brick may cause staining. Instead, look for a strong non-acid brick cleaner at your home and garden center.

Things You'll Need

• Brick cleaner
• Bucket
• Hose
• Stiff-bristle brush

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Instructions

1. • 1

     Dilute the brick cleaner in a bucket according to the directions for heavy-duty cleaning.

   • 2

     Wet the keystone with a garden hose until it's saturated. Spray it, allow the water to absorb, and spray it again several times until water sits on the surface.

   • 3

     Dip a stiff-bristle brush in the cleaning solution, and scrub the excess mortar. Allow the acid to sit for 5 to 10 minutes, and then scrub again to lift away the excess mortar.

   • 4

     Rinse the keystone well with the hose, and allow it to air-dry.