We live in a small ranch in New Hampshire and during the winter months experience a ghosting or yellowing on all of the inside walls of the house. This only happens during the winter months when the oil furnace runs. Two years ago, we had a brand new furnace installed and within the past six months a new chimney liner was installed. The house is equipped with cast iron radiators that were installed when the house was built in 1955. We do not have a fireplace and do not burn candles in the house. Can you provide any suggestions to the possible cause of this problem. Totally frustrated. Thank you.