i don't know what a "cow bell" is as far as tools go but i do know what a socket wrench is and if you get the correct size and gently tap it over the nut you should be able to get it off. don't worry about saving it cuz they're not expensive to replace.the when you install the new stem if you wrap the threads with some teflon tape it will be easier to remove the next time and since it will be easier you'll proberly never have to replace it.go figure...