We recommend the DOFF for use on surfaces such as brick, stone, concrete, tiled (glazed and encaustic), wood, faience and terracotta. The DOFF is also a useful sterilisation tool for kitchens, toilets, swimming pools, hospitals and factories. 0. Maximum Temperature. 0. Water Dispersed Per Minute. No Harmful. Residue. As the Doff uses superheated steam, there are no harmful chemicals being ...