Some contain phosphoric acid some an even weaker acid.
How to remove concrete from brick wall.
You may need to make several attempts to clean the brick before the cement is completely removed.
Then use a medium soft bristle brush to rub off any remaining mortar dust.
Most are safe to use on most materials.
However this method leaves the harder cementitious mortar in place around the brick which can be rather difficult to chisel away once the field brick is removed.
In the real world accidents happen.
Removing the discoloration as well as granular debris is a job for chemicals.
There are a number of ways that bricks can be removed from a wall.
See how i mounted it and watch the cleaning in action.
Once it sets it can be very difficult to remove without damaging the brick.
To remove dry mortar wet down the brick with a garden hose before tapping a chisel at an angle against the face of the wall to remove the excess mortar.
One method involves drilling a series of holes in the relatively soft clay of the brick then chiseling the brick out in pieces.
Options for brick removal.
You can buy a number of concrete cleaning solutions.
A hammer drill mounted on a saw horse seems to be the quickest way.