I just recently purchased a house that was built in 1905. It needed (and still does) TLC. The first thing I had to do before moving in was to get rid of a bad smell. I don't know if this is in any way related to your problem but all I can do is tell you about mine. I removed the carpeting and two layers of linoleum. The bottom layer of linoleum was held down with black tar which I believe to be the cause of my bad smell. It was a lot of work to remove the tar but it was worth it because there was a nice wood floor underneath and now the smell is gone. Also, I found an odor eater product that helped get rid of odors. I can't find a name for the product bu it has a toll-free telephone number printed on it (800-621-2943).