The answer is yes, but it takes a grinding machine to do it, and they are not cheap; if your end mills are dulling quickly, it could either be that you are over speeding them or they are of poor quality, they should hold up for a good while, also cutting steel without coolant or cutting oil will quickly dull a mill, brass or bronze, and cast iron can be cut dry, and aluminum should be lubed with kerosene or Tap Free or similar product.