Based on your scans, I don't think it needs to be conserved at all. In fact, unless there are more significant issues that are not revealed in your scan, disclosed conservation could actually harm the potential resale price. Residue and white out don't bother most OA collectors unless it's really distracting, which it's definitely not in your piece. They're part of the charm of vintage OA since they were produced for commercial purposes.
If you're planning on selling it anyways, I definitely wouldn't bother.