yup, I've done it for the kids crafting scissors for years... my gramma showed me that trick well over 35 years ago. I've got about 5 rotary blades that I've saved for when the kids do scrapbooking / papercrafting / cardmaking projects... I may try and sharpen one of those :)
My hubby is all zappy right now, so I will definitely try the dryer trick ~ we're tired of him zapping us!