How can i clean my uggs?

I have a pair of what use to be light tan uggs that are....not so light anymore. I lived out in the country when i first got them so they're filthy. How can I get them at least semi clean without going and buying ugg cleaner? I'm cheap and I dont want to spend any money on buying things expensive to clean them so whats a way i can do it just with simple supplies around the house?