I've always conquered bleed nipples with Plus-gas and as a final (and effective) resort a set of Snap-on stilsons about 75cm long - doesn't matter if the hex wears off, these herberts always do the trick. Make sure a new nipple is to hand (so to speak) before you use them. I've never seen anybody else have this bit of kit - they are about as long as a biro so can get in awkward places.