How do yo sharpen the blade of a handheld pencil sharpener?

Well the only way I would say to do it is usually the razor is screwed into the plastic part of the sharpener...so unscrew that and you can use a knife sharpener or just run the sides along a large flat stone and that should do it...or just buy a new one, because it might not be worth the effort to take apart and put back together again...good luck :)