DOFF cleans masonry using high temperature steam. While the temperature in the system is high the pressure on the surface being cleaned is gentle and uses a lower volume of water. The surface is not saturated and the steam dries in minutes.
Torc and Jos
Are lightweight abrasive systems that combine air pressure and water to remove staining. Used on stone/brickwork it is in effect a swirling vortex that delivers water to the surface using a nozzle gradually removing stainage until the surface is clean.
Poultice stone cleaner is usually used in specialist stonemasonry and conservation works. A paste is applied to the affected areas, then wrapped, left to cure and draw out soiling. Poultice does not require water and therefore favoured for delicate cleaning and stain removal on restoration jobs.