Although we’ve covered building and maintaining cob homes in the past, that might seem like way too much messy work for some people. So instead, why not just add a touch of earthen plaster to your already existing walls. This technique is a style of Natural Building, and it gives earthy accents to your home without changing much of its infrastructure. You can make the plaster out of materials like sand, clay and straw, and it can be applied easily by hand, or with a trowel. Take a look at this site to see if a new coat of Earthen Plaster is needed on your walls.