Masonry oven India, tandoors are traditional clay ovens, although these days modern electrically fired tandoors are available. The open-topped tandoor is a transitional design between the earth oven and the Roman-plan masonry oven. In the precolumbian Americas, similar ovens were often made of clay or adobe and are now referred to by the Spanish term "horno" (meaning "oven"). Horns are also traditional in the American Southwest. The traditional direct-fired masonry design is often called a "Roman" or "black" oven and dates in Western culture to at least the Roman Republic. It is known as a black oven because the fire generates soot
Conservation and restoration of ceramic objects and grease may be held on the surface loosely by electrostatic forces or weak chemical bonds and are easily removed. Some deposits, such as calcium salts, can be strongly attached to a ceramic surface, especially if the surface is unglazed. There are two main methods in which ceramics are cleaned and treated: mechanically and chemically. Not all ceramic pieces are dry when they need cleaning. Some ceramics, such as those that are excavated archaeologically, will be damp or wet in nature. Conservators tend to remove the surface dirt before the object is completely dry. This is done because it is