Ohio Rev. Code § 1345.24: Retaining notice of cancellation.

In a home solicitation sale, the seller shall retain, for the period in which an action to enforce the sale could be commenced, any notice of cancellation made pursuant to section 1345.22 of the Revised Code. The seller shall also retain any envelope in which a notice of cancellation is sent or delivered. If the date of delivery is not indicated or recorded on the notice of cancellation or on the envelope, the seller shall record the date of delivery on the notice of cancellation.