When an execution debtor owns any personal property which, if not exceeding a certain amount in value, is exempt from execution, and the officer levying the execution believes that its value exceeds the limit of exemption, he may levy on and sell it in the same manner as any other property. If, at the sale, such property brings an amount exceeding the limit of exemption, he shall immediately, on receipt of the purchase money, pay over the amount of the exemption to the execution debtor and apply the balance only on the execution; but, if a sum equal to the amount of the exemption is not bid for such property, he shall immediately return the property to the execution debtor. No money or property belonging or coming to any execution debtor under such a levy as is provided for in this section shall be liable to attachment.