Wash and dry nontoxic, untreated leaves, such as lemon or mint. In a double boiler, melt semi-sweet chocolate over low heat; stir constantly until almost melted. Remove from heat and continue stirring until all chocolate is melted. Then, brush the melted chocolate onto the back of each leaf. Refrigerate until the chocolate is set (about 10 minutes). Apply a second layer of chocolate; refrigerate again until set. Carefully peel away the leaf and discard. Refrigerate leaves until ready to use; serve immediately.