Wis. Stat. § 221.0304
A bank may take and receive personal property from any person for safekeeping and storage and may rent out the use of safes or other receptacles upon its premises upon such compensation as may be agreed upon. The bank has a lien for its charges on any property taken or received by it for safekeeping. If the lien is not paid within 2 years after the date the charges accrue, or if the property taken or received by the bank is not called for within 2 years after the date the charges accrue, the bank may sell the property at public auction. The bank shall provide such notice as is required for the sale of personal property on execution. After retaining from the proceeds of such sale all the liens and charges due the bank and the reasonable expenses of the sale, the bank shall pay the balance to the person who deposited the property, or to the person's legal representatives or assignees.
Wis. Stat. § 221.0304