Hi guys and thanks. It is not nicotine, mother didn't smoke. It is some time of mold or fungus I am sure. There is mildew on window sills etc but this is not mildew. It is a light brownish rust color and "growing" in round spots on everything. No sooty residue and it comes off clean when washed with tsp and chlorox solution. She was old and didn't need much air-cond. so I suspect it got started from a lack of fresh air and high humidity. It is not wood borers-it is on the wooden shutters, floors, wood-work and the wallboard-everywhere. Doesn't leave any whitish mark when cleaned off. Help guys!!!!!!