Mo. Rev. Stat. § 447.040

If no owner appear and prove the money or property within forty days, and the value exceed twenty dollars, the finder shall, within thirty days thereafter, cause a copy of the description to be inserted in some newspaper of general circulation, qualified pursuant to chapter 493, and located in the county where the money or property was found, once per week for three consecutive weeks; and if no owner prove the property within one hundred eighty days after such publication, the same shall vest in the finder.