If trapped between the taper and a raised left hand threaded section that doesn't engage any more . . . the bolt is a prisoner. So, 'with difficulty' and at risk to rest of your hair.
Of course, it may just unscrew clockwise as you exert 'pulling' pressure on the thing - the way it's meant to - but far too many won't. And then it's brutal methods, drills by stages, bit of dremelling maybe, until the shell of the thing can be collapsed and ripped out. Without having damaged the female left hand thread in the outer yoke, or the taper on the inner end, 'tis to be hoped.
CheeserBeezer may have a routine for doing this that he can share as he has done loads more than I have, but it's right up there on my Hate list of 'ways to waste half a morning'. PITA job and a direct consequence of asking the first turn of a thread to handle repeated extraction forces when turned one way, and then engage and come out when turned the other. Pretty disobliging of the cheapskates in the drawing office at Lucas and a subject that starts me off on a rant all too often!
