2. Cleaning and deveining is a tricky business. For a smooth terrine, you must remove the thick, branched main vein that runs through the center of each lobe. If you're experienced, dig into the middle of each lobe with a paring knife, catch the vein under its tip and pull it out. If you're a novice, probe for the vein and its branches with your fingers, pulling it out as you follow its length.