Every work of art, even stone or metal sculptures, need preventive conservation and care in order to be maintained in good condition. A sculpture may retain damage due to their method of construction, such as a bad firing in a ceramic work or flaws in a section of stone in a stone sculpture. Even if the work was made using both correct methods and materials, environmental conditions can still degrade or destroy a sculpture. For example, high humidity can corrode an iron sculpture and severe drought can dry out and cause cracks in a wooden sculpture. Sometimes the damage, like abrasions, fractures or writing/graffiti on the surface, is caused to the sculptures by human conduct. The museum's conservators ensure the sculptures are maintained properly, by selecting appropriate conditions during both their display and storage. When wear is observed on a work it is immediately transferred to the laboratory for maintenance. A range of maintenance procedures are used, including surface cleaning, restoration of structural integrity, welding of any fragmentation, aesthetic restoration of the work, and surface treatment. These procedures help to restore any damage, and help maintain the work retain its integrity longer by withstanding any future wear.