65 ILCS 5/8-4-12
Whenever there is a sum in the municipality's sinking fund in excess of the amount required for the payment of the municipality's bonded indebtedness maturing in that, or the succeeding, fiscal year, and the interest due in that period, the sinking fund commission may use this excess in the purchase of unpaid bonds for the payment of which, at maturity, the sinking fund was or shall be created, paying therefor no more than the market price. When such bonds are so purchased, they shall be cancelled, and thereafter no taxes for the payment of those bonds or the interest thereon shall be levied. The money in a municipality's sinking fund may be applied to the payment of such bonds without any further appropriation by the municipality than is made under this section.
65 ILCS 5/8-4-12