I keep a small nail file in my handbag beauty kit, in case a nail develops a snag. A whoosh or two back and forth underneath the desk is fine (I hope). Because I'm the only woman in the building, I'm able to keep certain items stashed away in the ladies room, and this is where I go to "take care of things".
Good grief, basic grooming needs to be done at home. Clipping toenails at work? Or - have you ever noticed how many people start picking their nose at a red light? I notice this a lot, because I'm on the bus / trolley car and observe from my perch.