Carbon nano-onions (CNOs) represent a still largely unexplored carbon allotrope. Promising properties of these unique carbon structures are driving the research efforts in this area, but many technical problems remain in their preparation, derivatization, separation and characterization. In this article, we report the preparation, partial purification, and multiple functionalization and solubilization of CNOs. With only one priorly published short communication describing CNO functionalization, the present work is the most comprehensive description of CNO functionalization and characterization to date.