DOFF is a steam based stone cleaning system. It’s unlike any other steam system and can achieve temperatures of up to 150°C at the nozzle end – making it a ‘superheated water system’. The operator is able to vary the temperature and pressure to remove many different types of paint and biological matter. What can DOFF be used for? The steam/superheated water will remove moss, algae, fungi and other biological matter and will also kill off spores. This means there’s then no need to use a chemical biocide during the removal process or as a protection against further biological activity. How does it work? DOFF cleans stonework and masonry using high-temperature steam.