Money obtained from the use of such building shall be deposited in the city treasury to the credit of the proper fund and applied, in order, to the following purposes exclusively:
(a) The necessary expenses of maintaining, insuring, and making improvements and repairs on, the hall.
(b) Payment of interest and principal on the bonds.
(c) The surplus remaining may be appropriated and used for general municipal purposes.
(Added by Stats. 1949, Ch. 79.)