Many people sharpen their knives using metal files. The problem, however, with metal files is that they sharpen the knives by grinding away the metal very quickly and do not produce a refined, polished edge. Grit whetstones are easily available, too, and if you are looking for one, the Intelitopia grit whetstone kit available on Amazon is definitely worth a look. The reviews on Amazon consistently mention that the stones sharpen the knives properly and are good value for money, too. Just keep in mind that there is a learning curve to using grit whetstones.