A shaping process where an abrasive tool or substance is rubbed against a material removing excess or unwanted parts. This is often used during the finishing of an object to smooth surfaces and edges that may have been formed by other processes. Filing is carried out on a wide range of materials like metal, wood, plastic and glass. Filing is usually done with a hand tool; normally a hardened metal bar with sharp teeth or ridges on its face known as a file. Sand paper is used to file materials like glass.