So, lnhammer has conclusively proven that even had I carefully read and followed the directions on the back of the package, the dried taro stem I tried to poison us with still wouldn’t have been edible. In addition to following those instructions better than I did (boiling followed by 24 hours of soaking with regular rinsing), lnhammer took the hit for the household, and tasted the results.
Apparently, when you follow the directions, the tingling goes down more quickly, at least. Surely that counts for something.
I admire the people who figured out how to eat this vegetable. I think, alas, we may lack their boldness; there won’t be a third attempt. Not with this particular form of the stuff, anyway.