After completing canvassing procedures, a local board shall retain all voted ballots in a sealed ballot box labeled with a batch label until they are authorized to be opened and removed for an audit, recount, judicial challenge, storage, or disposal. Document Retention. A local board shall retain for 22 months after an election: Absentee ballot applications; Voted absentee ballots; Return envelopes; and Certificates of assistance. Disposal of Unvoted Ballots. A local board may dispose of any unvoted absentee ballots at least 30 days after State certification of an election or the conclusion of a recount, whichever is later. A local board is not required to shred unvoted absentee ballots.