(a) After jurors are impaneled and serve at least four days, the clerk or his deputy shall open the envelope containing the jury wheel cards with names that correspond to those on a jury list from which the impaneled jurors were selected for jury service.
(b) On opening the envelope, the clerk or his deputy shall immediately return to the jury wheel each card in the envelope with the name of a person who was not impaneled or who did not serve at least four days and shall place in a box, for use by the next officials selecting names of persons for the jury wheel, each jury wheel card in the envelope with the name of a person who served at least four days. However, the clerk or deputy opening the envelope may withhold from the jury wheel all cards selected for that jury list unless the judge orders him to return the cards to the jury wheel.
(c) If any of the jury lists drawn for a term of court are not used, the clerk or his deputy, immediately after the expiration of the term, shall open the envelopes containing the jury wheel cards with the names that appear on the unused lists and return the jury wheel cards to the jury wheel.