If you go the open up option you may lose a good selling point of unopened. If it was switched off before it’s long dip, there’s some hope. If you go the open up option I’d get a bottle of 99% IPA, (not the beer) isopropyl alcohol . An old toothbrush and some cotton buds for cleaning. Then a new battery and screen. Even if the screen works which I doubt it won’t look right if water got between the layers. You’ll need to strip the whole thing down cleaning every connector and component with green corrosion on it. If it was powered on when it had it’s dip then the odds of it being easy to fix plummet dramatically. Just my thoughts .