I know all about that! Part of the house here is over a crawl space. There was a spot last year that animals could get into. A skunk did. First time, it wasn't so bad, although at the time it seemed awful. I went to the basement and saw the dude headed the other way. I think he was out then. Well, I blocked off the opening they were entering through, and this time I think it got scared. It was so bad that we went to dinner later that evening, and the hostess said something about smelling a skunk outside. Well, we sat down ad realized that it was us! We had smelled it so strong that when we left we didn't notice the weaker, more typical smell. Ugh. It took about a week for it tl cear out pretty well. Then I could talk about the chipmunks that get in from time to time, or the birds in the ceiling... Oh the joys of living in an old farmhouse!