If I remember correctly...
November 04, 2012 | 05:43 PM can turn unclaimed property of any sorts (including cash) over to the police or sheriff's department. If the property is not claimed after 90 days, you then become the rightful and legal owner of said property. The law probably variates from county to county and state by state, but I remember this from a relative that found a grocery bag in a parking lot filled with about $1,000.