PB Blaster would work BADLY as a cable lube. It's far too thin and too volatile to do any real good. For my own part I rub a film of Park grease into the cable before I thread the housing on and I've yet to have any real problems with sticking cables.
This is why you shouldn't trim your cable ends too short, because even if the ends get frayed you should be able to trim them back to a clean end for re-threading. Crimp-on caps are cheap and do more than just keep you from hurting yourself.