The only one I ever had that "failed" was one left for several years in the trunk of a beater Cadillac I had. The trunk leaked, and the poor thing mildewed. Completely unsmokable.
I only had one MM
"fail" on me as well.
I have no idea what the deal with that cob was -
and, I had many great MM smokers prior to the one in question - but, right from Jump Street, it gave off the worst burnt cob or wood taste and smell. I may have accidentally burnt the stem where it appears at the bottom of bowl... who knows.
I throw it end-over-end right over the hedge of the one neighbor I didn't like.
Anyway, after that, to break a new cob in for the first time, I always prep my MM Cobs by coating the inside of bowl and the upper rim with either Honey or Maple Syrup, and, let the bowl dry to a hard shellac in a day or two depending on the humidity level and how heavily you coat the pipe.
Then,
"Fill, Fire, and Smoke".
You could repeat the process if you like, but I have never found the need to do so.
It's an old-timers trick that works just great for me; and, I love my honeyed MM cobs.
Here's a picture of one of my all-time best smokers, which got both the honey AND the maple syrup treatment during it's breaking-in, which was years ago; and, I just smoked it the other night:
About 100,000 miles on that bad boy, and still going strong as ever. -
Sherm Natan