All ballot boxes shall be rigid wood or metal containers. Ballot boxes shall be furnished at the expense of the town where they are to be used. When not in use, ballot boxes shall be in the custody of the town clerk. During voting hours there shall be signs, provided by the Secretary of State, placed on or near ballot boxes telling voters to deposit their own ballots in the ballot boxes. This requirement shall not apply to the ballot boxes used during primary elections for the collection of unvoted ballots, in which instance unvoted ballots are inserted by election officials. (Added 1977, No. 269 (Adj. Sess.), § 1; amended 1979, No. 200 (Adj. Sess.), § 57.)