I have always used a dremmel, then a finishing file to smooth. But on dogs with really dark nail, it is nearly impossible to see so I do a very small amount and check,drill, check .
@BasenjiByTheBay:
Haven't made it through all of them but what great wrinkles on the little guy. Too cute!
Yeah he has a perfect wrinkles :). He is a one of the few with this wrinkles in Czech Rep.