Harvest dandelion root in autumn when the plant has had a full growing season. Use a shovel and dig deeply down around the plant. Dandelion taproots can be 5 to 10 inches deep. Shake off the excess dirt and rinse the root.
Fill a sink with water and soak the root for 10 to 15 minutes to loosen any ground-in dirt. Use a soft-bristled scrub brush to remove much of the dirt and any moldy spots.
Use a sharp knife to remove any remaining mold. Cut around the mold so the knife doesn't push spores into the vegetable. Wash the knife between cuts so you don't spread the moldy spores into the vegetable. Wash the root well after all of the mold is gone.
Use a potato peeler to remove the film on the outside. Wash the root well after peeling. Cut the top and bottom off the root.
Cut up the root into 1-inch chunks and soak them in a bowl of water for an hour. Pour off the cloudy water and use the roots to make tea, coffee or in stewed vegetable dishes.