We’ve been using the humanure composting system since 1996. At the field school, we’ve simplified it down from a sawdust toilet. Now it’s a forest duff toilet. The goal was to use only materials we could gather on site. Now we cover fresh deposits with duff; the mixture of leaves and dirt that makes up the forest floor. To cover material on the pile, we cut weeds with a scythe and put them on the pile. The water we use is rainwater. A regular sawdust toilet is sustainable. Our variation is sustainable and uses no outside inputs. Simple, effective and green.