Records open to public inspection

All pleadings and evidence, documentary or otherwise, including the transcript of the stenographic report of the hearings held before the board in any matter to which its jurisdiction shall extend, shall be public records, open to the inspection of the public; except that after the decision of the board in any proceeding has become final, the board may, upon motion of the taxpayer or other contestant or the collector, permit the withdrawal by the party entitled thereto of originals of books, documents, records, models, diagrams and other exhibits, introduced in evidence before the board; or the board may, on its own motion, make such other disposition thereof as it deems advisable.