No person shall willfully make any false entry in the accounts or records of any public utility, or willfully destroy, mutilate or by any other means falsify such accounts or records, or willfully neglect or fail to make full, true or correct entries of all facts and transactions appertaining to the business of any public utility, which it is his duty to make; provided, that the commission may at its discretion issue orders specifying operating, accounting or financial accounts, records, memoranda, books or papers of public utilities which may, after a reasonable time, be destroyed, and may prescribe the length of time the same shall be preserved.