So, I'm a newbie brewer (my most recent batch was my fourth) and I'm still inventing new mistakes each time we brew.
My most recent brew day was about three weeks ago. After the unfermented beer had been transferred into the carboy, I put a stopper (still wet with sanitizer) in the top and the pushed the airlock into the hole of the stopper. Only... that's not what happened.
The force of pushing down on the airlock was evidently greater than the upward resistance of friction between the tapered (also remember wet) stopper and the glass neck of the carboy. The stopper went straight through into the carboy.
Okay, the immediate problem wasn't so great, the stopper had been sanitized, so I wasn't too worried about it spoiling our brew. The stopper remained in the carboy throughout fermentation. We simply put another one in and went about our business.
Now the stumper. How to get it out before our next brew day? I suppose the stopper could have remained in there forever, but I just didn't feel it would ever get truly clean in there; it might spoil the next batch.
My buddies and I contemplated this for the three weeks that the porter sat in fermentation. Most of our ideas fell into two categories: 1. fish a weighted string through the hole in the stopper and pull it out, and 2. harpoon the stopper with something long and narrow and try to pull it out. Busting the glass would, of course, be effective, but would defeat the purpose entirely.
Well, the stopper is out and we did none of these things. While washing bottles on bottling day, I remembered an episode of Scam School I watched a while back (link below). This trick worked like a charm; we got it out on the first try in about 30 seconds.
So perhaps none of you have been dumb enough to have this problem, but if you're unlucky enough to have done so, check this out: