65 ILCS 5/9-1-10
Whenever any municipality creates an unclaimed rebate fund and by ordinance directs the use of the money in that fund for the purpose of paying rebates or refunds due on any warrant for any special assessment or special tax, the equivalent of any such money so used shall be returned to the unclaimed rebate fund as soon as the warrants, which were deficient, have been collected. Whenever any municipality directs the use of the money in that fund for the purpose of paying unpaid special assessment vouchers or special assessment bonds or special tax vouchers or interest or deficiency in interest or public benefits in any warrant in which there is a deficiency, the equivalent of any such money so used or any part thereof shall be returned to the unclaimed rebate fund in the event there is collected in the warrant any surplus in excess of the amount required to pay the bonds and vouchers issued to anticipate such warrant. Whenever any municipality directs the use of the money in the fund for the purpose of purchasing any lot, block or tract or parcel of land, or any real estate at any sale had to enforce the collection of special assessments or special taxes, the proceeds of any redemption from such sale or from any sale of the certificate or title acquired by such sale, to an amount equivalent to any such money so used or any part thereof, shall be returned to the unclaimed rebate fund.
65 ILCS 5/9-1-10