We travel across the country to find industrious and ingenious Americans who prove they're not afraid to roll up their sleeves and get their hands dirty to make a living. Dealing in the diverse, exotic and, even occasionally, cringe-worthy underground economy of crud. Eels, mushrooms, ginseng, bloodworms and burls are important natural resources. Their harvesting goes back many generations and is now subject to federal, state and local laws. Anyone contemplating these activities should follow all legal requirements and sustainable practices.