Section 11. Any corporation organized under the preceding section shall have power to mortgage or pledge its real or personal property and to issue promissory notes or other evidences of indebtedness. Such corporation shall also have power to establish reserves and invest the funds thereof in such manner as it may deem advisable or as may be provided in its by-laws; and to exercise all other powers, rights and privileges necessary or incidental to the purposes for which said corporation was organized or to the activities in which it is engaged; provided, however, that no such corporation shall handle the products of any non-member, except for storage.