Battery's

[Chamberpains]

You'll often times smell them cooking too if there's a problem internally. It'll be a rotten egg sulphur smell and the 1's cooking will be hot and usually smoking.
Sulfuric acid gas (hydrogen sulfide) may be funny to remind you of throwing stink bombs in the hallway at school. But it's definitely not good for the lungs.

*** That's funny. I love some of the auto correct word changes on this forum. Its not terrible egg its r.o.t.t.e.n egg smell. Hahaha