Section 8A. Any provision of general or special law to the contrary notwithstanding, the clerk of any city or town, with the written approval of the supervisor of records, may destroy any index of instruments made by any clerk of such city or town under the provision of law now embodied in section fifteen of chapter forty-one or any original record made by any such clerk under any of the provisions of law now embodied in section eleven of chapter two hundred and nine, section three of chapter two hundred and fifty-five, or any similar statute; provided, that such index or record, as the case may be, has been, or shall have been, micro-photographed, and that twenty years has, or shall have, expired after the making of such index or record. The micro-photograph of any index or record so destroyed shall have the same force and effect as the original index or record from which such micro-photograph was made.