Bus smoke! Don’t breathe this!
Seriously. Wear a mask. That thick white powder is zinc oxide. You know, the stuff that makes welders sick? While I was smart enough to wear the mask for the bulk of today’s experimental scrubbing in a dry area, I failed to do so in a patch at the back door. It wasn’t much, but it was enough to make me feel like crap. It isn’t just for welders to keep in mind.