How do you remove rusted threaded pipes?

You are going to need a good wrench with a long handle and some thread loosener. You need to soak the threads in liquid wrench or a similar lubricant as much as possible. This is necessairy to free the pipe as apposed to just twisting it off. Remember to thoroughly flush the pipe afterword, as some will get inside and you don't want thread loosener in your water supply. You can also use a "cheater bar," a bar or pipe used to extend the wrench handle, to give you more turque. Be carefull with this as you can twist the pipe off, ruining both fittings you are trying to save. Good luck, and hopefully your vocabulary is up to the task.