Cast-iron cookware
Because other cookware cleaning techniques like scouring or washing in a dishwasher can remove or damage the seasoning on a bare cast-iron pan, these pans should not be cleaned like most other cookware. Some chefs advocate never cleaning cast-iron pans at all; simply wiping them out after use, or washing them with hot water and a stiff brush. Others advocate washing with mild soap and water, and then re-applying a thin layer of fat or oil. A third approach is to scrub with coarse salt and a paper towel or clean rag.
SoHo, Manhattan
During cast iron's heyday, many architects thought it to be structurally more sound than steel. It was also thought that cast iron would be fire-resistant, and facades were constructed over many interiors built of wood and other flammable materials. When exposed to heat, cast iron buckled, and later cracked under the cold water used to extinguish fire. In 1899, a building code mandating the backing of cast-iron fronts with masonry was passed. Most of the buildings that stand today are constructed in this way. It was the advent of steel as a major construction material that brought an end to the cast iron era.