This Instructable shows how to build a trommel (rotary screen) for sifting compost or shredded leaves. The purpose of sifting is to separate coarse unfinished compost materials from the finished product or to separate out trash and debris from other organic materials before use in the garden. My city has trucks that go around sucking up all the leaves in the fall. These leaves are then placed in a huge pile and allowed to decompose. I can go get decomposed leaves from them as needed but they often contain trash and rocks that need removed so I'm planning to use this trommel to sift that material as well as compost. Sifting also makes organic materials appear more uniform which is desirable if you are using them as a top dressing or mulch.