Hello, I hope you can help me solve this mystery. Over the last two weeks, black dots have appeared on many surfaces in my apartment: in the sink, counters, on some walls, and heavily on the kitchen and bathroom floors, which are linoleum and tile respectively. When I've swept the floor, half of what I pick up are these dots, there will be hundreds. the rest of the apartment is hardwood, so they may be there and I just don't see them. I've wiped them off and they keep coming back.
They are all the same size (about a mm in diameter) and are perfectly round. They don't appear to dissolve in water, and are very flat, and very black. They will adhere to the surface, but will come off in one piece with scrubbing. They are not evenly distributed, they will appear in clumps. I assumed they were insect related, and from reading other posts, it could be left by flies, but I'm puzzled in that I haven't seen any evidence of flies, moths, or any other pest. And there are so many dots, seems that I have an infestation.