It is important to have a nice set of metal files if you do wirework or metal smithing. Metal files will all scratch the metal or wire while you file – that is a natural by-product of filing metal against metal. Only use the file in one direction – don’t push it back and forth or that will defeat the purpose of sanding your project to a nice finish. The smaller the grain on the files, the finer the sanding job you will do. After you are finished filing off rough spots and making your wire or metal smooth, you can progress to a fine sandpaper (600 and up to 2000 are appropriate grits for jewelry) or a smooth sander for a hand drill to get rid of any scratch marks.