Cleaning up /pointing brick
I deciding to expose an old chimney in our house, and the brick work was repaired pointed at some point, i believe with cement and not S mortar. The chimney is lined, and I really don't want to tear out the cement to put the right mortar.
But whoever did it did not clean off the bricks well, I started using some old sandpaper just to see and it seemed to take the cement off pretty well, as well as the top layer of dirty brick. Could I do this, and just seal the brick with some sort of polyurethane?