A substrate-friendly method to synthesize metal oxide nanostructures by directly heating metal-foil in air using a hotplate was analyzed. Co and Zn films were deposited on different types of substrates and heated the films at various temperatures in air. It was found that the hotplate method can provide reasonable control of the morphology during synthesis of metal oxide nanostructures. The results show that the hotplate method can be a powerful material supplier for further fundamental research and industrial applications.