Block is ultrafine non-metallic polishing compound bonded in an elastic material which wears evenly. It cleans degreases & polishes in one clean simple procedure totally eliminating the need for abrasive pastes water washes & solvent washes. It has been designed primarily for cleaning copper-clad boards prior to application of resist inks or finished circuits prior to tinsilvergold plating. It is equally useful for cleaning contacts switch gears potentiometers connectors adjustable transformers etc. Supplied individually.