When I last mentioned the office project we were knee deep in dust. Since then, the wall has been "chaux'd" and looks really good.
The process itself is very simple, but physically hard and very time consuming.
water until it becomes "like the shit of a cow"
2: Wet down wall with water and apply mixture to the wall,
pushing it hard into the gaps between the stones
3: Wait at least 30 minutes, then brush back
the excess chaux with a stiff bristled brush4: Allow to dry for weeks. The chaux will take
longer to dry the thicker it is applied.