Wis. Stat. § 24.36: Lost certificates and patents.

Whenever any duplicate certificate of sale has been lost or destroyed before the patent has been issued, or whenever any patent has been lost or destroyed, the board, upon satisfactory proof of the fact, established by affidavit filed with the board, may issue a certified copy of the original certificate of sale or of the record in the board’s office of the patent, or a quitclaim deed in place of the missing patent, to the person entitled to the copy of the certificate or record of the patent, or quitclaim deed, which shall have the same force and effect as the original duplicate certificate or patent. The board’s certificate to the copy and quitclaim deed shall recite the loss or destruction of the original.