Ray, I use dirt as well, but for under the pan and around the jaws the ant hill chaff works great. There is a wax substance on the chaff that repels water and prevents freeze up. The dirt is used on the top layer. Another thing I like about it is that during the thaw / freeze season, it doesn't wick up the "dew" moisture like dirt does, and I feel comfortable my sets are working during below freezing nights.
Just so you don't think we're crazy...lol