Within 30 days after the maturity of the last installment of any issue of bonds for the local improvement district, if any such bonds remain unpaid, any property remaining unsold, to which the municipality has taken title or on which it holds a certificate of sale, must be offered for sale by giving notice of the time and place of sale by publication and by mail. At the time and place designated in the notice, the treasurer shall offer such property for sale to the highest bidder. Upon the sale of any property and payment therefor, a deed shall be executed to the purchaser in substantially the same manner as herein provided for the execution of deeds.