Steel Brush. This is a nice soft steel brush that gently polishes the copper, bronze and silver-clay after firing. will scratch up the surface, some people brush with soap and water.
Brand
Silver Clay
WARNING: This product can expose you to chemicals including Silica, crystalline (airborne particles of respirable size), which are known to the State of California to cause cancer. For more information go to www.P65Warnings.ca.gov.