It is a genuine pain most definitely. Stanley knife or razor blade cut the whipping on every rod, taking care not to cut the blank, then removing the old thread completely. Sanding the blank down to get rid of the rubbish left, then rewhipping the rod rings back in the right places, followed by a decent coat of a good resin on top of the whipping. Then, a thin mix of rod lacquer or varnish over the top of everything.
The strip and clean will likely take a day in itself, whipping the eyes back on, dependant on how fast you are, and what equipment you have, half a day. Resin the whipping, and allowing that to dry, while having the blank turned regularly (or continually), at least 24 hours. Lacquering the rod, and that drying, again another day.
I can do it, have done it, but if I told you I hate doing it, and would charge around the same price as a new mid range rod, £150 ish, then as Yonny says, you are better off having a new rod.
Out of interest what make and model of rods are they?