I have a mystery...
In a few corners of our house there are very tiny specks of something dried onto the floor tile. One of these places is behind the corner of the drapes by a patio door. Another is just under the cut glass window in the front hall. The third was in the back corner of the rarely opened front hall closet.
The substance can be removed with a wet cloth. But it seems like the very tiny specks are in layers rather than something that was sprayed all at once.
The picture above is actually somewhat enlarged.
One thing these places have in common is that they are below spots where spiders weave their webs. I think I slurp up a spider or three every time I vacuum that corner in the hall, and there sure were a lot of cobbley webs when I took the drapery down. There were webs in the closet too.
It is my guess that it is Spider poo.
Bears leave scat, birds drop "whitewash," aphids leave "honeydew," so what do spiders do?
What do you think?