Note: Used properly, the MusicNomad diamond-coated nut file will last a very long time. Originally known for industrial applications, diamond is considered one of the most durable abrasives around. Only use these files for nuts made of bone, graphite, plastic or TUSQ materials, or for brass or zinc tailpieces. The files are not suitable for grinding steel. Clean the files regularly with a brush to remove grinding residues from the gaps in the diamond coating. If the grinding effect on the front part of the file wears off, the file can be turned in the handle to bring the less-used rear part to the front.