The last K&T rework I did I was able (with the help of a Stanley mini-prybar, a flashlight, and an inspection mirror) to pop the knobs off the studs and use the old linen covered wire as a pulling means.
WATCH OUT FOR "HIDDEN" TUBES" (usually under debris in the stud space. Depending on the direction they were driven they can either "pop" up towards you, or they have to be broken out. There were several that were "doubled up" on penetrations @ floor level (1/2 of a tube capped by a regular tube... P.I.T.A) that were heck to remove.
