That pipe is screaming "HELP, CLEAN ME!!!" Only thing that will make that stem better is sandpaper, it is very heavily oxidized. Walker Briar Works cleaner wouldn't affect it at all. I'm glad you got your fathers pipes, I restored the ones my dad has and gave them back in near new condition. Use 1,500 grit or higher sandpaper as the last step, before that, some 600 works fine. Since the sandpaper is less hard than vulcanite, it will not remove the stem, only the oxidization.