+1 HillRider

If you are disposing of the parts to replace with a sealed BB, then have at it with a hammer and punch. If you plan to reuse the parts, two inexpensive wrenches will get the job done properly and you'll be able to use them every time you regrease and adjust the BB. There are advantages to cup and ball BBs, but convenience isn't one of them. If the old BB is well used, it is worth it to pull the fixed cup for inspection and if you are replacing the entire BB assembly, always replace the fixed cup at the same time. The vise method works pretty well most of the time, but if you have a stubborn one, your LBS will have a job specific tool that locks onto the flats making removal almost fool proof. Once you have the spindle and bearings out and most of the grease removed, spray a little penetrating oil into the BB shell with the fixed cup down and let it sit for an hour or two to make removal easier. If you are really lucky, the fixed cup will come out with minimal persuasion. Other times, you'd swear the thing was welded in. As mentioned, pay attention to your thread direction.

Don't try to remove the fixed cup with a big water pump pliers (aka Channel Lock) or even a big cresent wrench, the result is usually rounded flats and busted knuckles, probably a ding in the paint to boot.