We are working in a house with a mysterious problem – brown drops appear only on the hall walls, surface of the paint. The drops are waxy, greasy. When cleaned they re-appear in about a month or two.
one story with basement/ hip roof/ medium well insulated (loose fibreglas)/ hot water heat/ natural gas/ flu pipe is close to hall (in closet), 6 doors enclose the 4 ft x 8 ft hall/ house used to heat mostly with wood (chimney was about 25 feet away from hall, now is removed)/ loose fitting and untrimmed pull down stairway in hall – see pic)/ not sure about attic ventilation, forgot to check sorry/
Any idea of what this might be?