This restriction helps with issues of pests and odors. A popular way to compost food wastes and small amounts of paper is a worm compost bin. Worm compost bins have been called organic garbage disposals. The worms live in paper bedding into which kitchen scraps are placed. They eat both the paper and the kitchen scraps and excrete worm castings.
Castings are far more potent than compost made from a backyard pile.
There are more nutrients in castings, and they are in a form that makes them even more readily available to vegetation. People often question why this process doesn't smell. It is actually the rotting portions of decaying food that stink. In worm composting, the worms eat the rotting portion. The fresh portion is then exposed to the air and begins to rot.