35 ILCS 200/21-100
The county board or corporate authorities of the county, or other taxing district acquiring property under Section 21-95 shall give written notice of the acquisition to the chief county assessment officer and the county collector and the county clerk of the county in which the property is located, and request the voiding of the tax liens as provided in this Section. The notice shall describe the acquired property by legal description or property index number.
Upon receipt of the notice, the county collector and county clerk shall void the current and all prior unpaid taxes on the records in their respective offices by entering the following statement upon their records for the property: "Acquired by ... (name of county, municipality, school district, or park district acquiring the property under Section 21-95). Taxes due and unpaid on this property ... (give legal description or property index number and address of the property) ... are waived and null and void under Section 21-100 of the Property Tax Code. The tax bills of this property are hereby voided and liens for the taxes are extinguished."
35 ILCS 200/21-100