That's not too bad. Be glad they weren't in the flashlights. Many years ago, I had to throw away several mini-Mags (had a collection of different colored ones) and one full-size flashlight (torch) because the batteries had leaked inside, bonding the cells to the inner wall or welding the cap on so you couldn't get inside. That's when I began my crusade to eliminate alkalines from my life.
I lost a beautiful vintage USAF inspection light with interchangeable perspex light guides and 2 different mirrors to a pair of those evil bunnies that way. I was not able to get the front one out, even using a drift punch. At one place, they have eaten through the tube.
Cor this thread is just depressing accounts of death and acid attacks this morning. Sounds like BBC News
I'm tempted to grab some of those Ikea NiMh cells after reading the above. They are apparently pretty good.
@Kosmic: that's what happened to the one I had that exploded.
You left out the fire. Nowadays, it is common part of a safety and facility indoctrination that workers are told where to put used batteries. That always something I am waiting for. When I ask for details, I am regularely shown a cardboard box with a hole in the top, where people should insert their discarded batteries until the box is full.
That is when I ask what they assume is happening IN that box and if they ever hat a look into it. As opposed to the spider-in-the-vacuum-scare, taking that look can reveal oxidative horrors.
It is a fact that in multiple instances those battery recycling boxes have started fires, with just non-combustive contamination in certainly even more cases. In one case a test lab or electronics workshop was affected. It is by the mechanism of leakage and also by the danger of a closed circuit spontaleously forming over a number of those galvanic monsters by shifting or dropping the missing one in.