Steel scurbber ball,another name called kitchen cleaning ball. Always used for home or office cleaning,can remove the dirt in surface powerfull,they are balls made by thin steel  wire.Because of the large friction , the steel ball is generally used in the objects which surface 
is not easy deformated caused by friction, 
such as the bottom of the pot ( except for the pan with coating) , stove , stainless steel appliances , etc.