I battled this with my Duncan after my (former) clown made a home in it. I lost about 1/3 of it in the process, but I kept the mush off with a turkey baster, dipped it in lugols and revive (not at the same time and on separate occasions). Took a while, but it bounced back minus the part of the stock I lost.

In the reading I have done on it, many people recommend fragging off the bad parts, but there is no guarantee in that either.