RUBBX6255, Rubrite Flexible Abrasive, Size 1/2" x 3/4" x 5" Rubrite flexible abrasive cleaning stones are excellent for removing surface imperfections from any metal. Mildly abrasive, they do only enough cutting to produce a high polish and fine finish. They are slow-wearing, non-loading, and will not gum or dust. Recommended in commutator maintenance for periodic cleanup of surface, or for polishing the commutator after grinding with Diamond D commstones. They can also be recommended to provide a smooth, clean finish on machined parts, etc. This type can be used for hundreds of jobs - including metal cleaning, commutator burnishing and rust removal.