I have these mysterious spots in clusters that appear at the edge of walls, along this door arch in our house, and on door frames. I also see them though in much smaller quantity on the kitchen cabinet doors. I clean them, they reappear! It's mainly in the area in the vicinity of the kitchen. A couple of spots also on the opposite wall of the living room. Nothing in the bedroom. I'm attaching images, the spots are yellowish-red. I thought at first they were splashes from the kitchen but now they have appeared even near the ceiling, and they are so many, definitely not just oil or food drops. They seem to prefer edges over anything else. Help??