Ohio Rev. Code Ann. § 3315.03

The board of commissioners of the sinking fund shall invest that fund in bonds of the United States, of Ohio, of any municipal corporation, county, township, or school district of any state, or in bonds of its own issue. All interest received from such investments shall be deposited as other funds of such sinking fund, and reinvested in like manner. For the extinguishment of any bonded indebtedness included in such fund, the board may sell or use any of the securities or money of such fund.