With constant evaporation wet parts of waste will loose some volume, providing a healthier and well balanced compost. This also prevents all kinds of pests, flies, smells and leakages.
Some like them, some don't, but composting remains possible even without worms. In natural soils, mushrooms, bacteria and micro fauna species turn organic matter into humus, with the worms only giving a final touch.
We use furniture-grade fabric and wood for indoor silos, weatherproof PVC canvas or metal finishing for outdoor ones. Our silos are somehow stylish, ranging from sober black to bright colors and flashy designs.