It may be possible that you have, or have had, cats under your house in the crawlspace. During the winter, I had a cat get under my house, and the dryer smelled for weeks. I am moving out this week, and when we removed the dryer vent that connects the dryer to the crawlspace that's all you can smell is cat urine. This is a rental, so I'm searching the web for ideas of how to get rid of the smell - I don't need my landlord thinking I had cats it house!
