What makes this sanitary and earthy smelling instead of just a bucket of crap is the cover material.
Cover material can be grass clippings, Peat Moss, Coconut Coir (recycled coconut fibers), ground up corn cob, or even sawdust (raw wood preferred, not kiln dried). Our favorite is the Recycled Coconut Coir (a waste product from the food industry) and the ground corn cob.
Put about 3" in the bottom of the bucket before use to act as a liquid absorbent and after every deposit, cover with another inch or so. http://goo.gl/xZAyT
Some folks use a plastic bag liner, especially when camping. This makes it easier to keep the bucket clean, but harder to compost, as the bag needs to be disposed of. Biodegradable
bags exist, but still problematic for composting. Perfect for camping in the woods.