Where does the dirt go?

I have been wondering how Trixie manages to stay white-ish. She's digging like crazy in the backyard and it's been raining. Oh how I HATE mud, rain, dirt, etc. The picture above was taken right after she dug IN the rain. What a lucky duckie! So yeah, I wanna know....where does the dirt go?

Answer: The white blanket that she sleeps on inside her crate. I clean it every 2 weeks. It's a regular blanket that I've folded up so it fits inside. You can clearly see the white part (the bottom half of the picture) where she DOESN'T touch it, and the top part of the picture which is where the mud and dirt goes. Maybe it's time we teach her how to wipe her paws?