Tiny black sand falling from old wooden ceiling - what is it?
May 10, 2016 3:08 PM Subscribe
I've worked in a couple of old wooden buildings in downtown Toronto. The interiors look like this, more or less. Little hard black bits occasionally fall from the ceiling, about the size of sand grains. They are hard. Sometimes they land in my lunch. Any idea what they might be? I'm guessing some kind of preservative, maybe creosote?