The election returns from each ward, immediately upon the completion of the count and certification of the election board, shall be filed with the clerk, who shall immediately place them in the safe or vault in the said clerk's office, until the same shall be canvassed by the mayor and council. After having been canvassed, said returns shall be sealed up and kept by the said clerk for two (2) years, and no person shall have access to them, except on the order of a court of general jurisdiction.