Rene Lamontagne wrote:

I once took a breath out of a bottle labelled paintÂ* thinners, Some
asshole in our cleaning staff had filled it with pure ammonia without
relabeling it, Well I nearly passed out and couldn't breath for a couple
minutes, so be careful.

30+ years ago, one of our customers was a PCB manufacturer, one part of
the building consisted of an ammonia bath, I didn't like walking through
that part of the factory, the owner said it was good as none of the
staff in that section were ever off with coughs and colds!

Surprisingly for a pretty small factory, competing with cheap chinese
PCB manufacturing, it's still operating today.