Section 5H. For the celebration of the year 2000 or the year 2001 or any centennial celebration, any city or town may appropriate money annually during the five years preceding such year. Such city or town is hereby authorized to establish in its treasury a special fund in which shall be deposited such sums as may be appropriated by it under the provisions of this section, and any and all sums received by way of income from the sale of commemorative items or from admission charges for commemorative ceremonies or events. All such sums received by the treasurer shall be kept separate from other moneys, funds or property of such city or town, and the principal and interest thereof may, from time to time upon the authorization of the mayor or city manager, as the case may be, the board of selectmen, or the majority of any special committee established to plan such celebration, be expended for the purposes of such celebration in the year of such celebration and in the year preceding or succeeding same. There shall be an accounting to the treasurer for the expenditure of all funds. Any surplus remaining in said special fund after such celebration is concluded shall be transferred by the treasurer into the treasury of such city or town.