Even if you’re not going to restore them right away, I’d suggest removing the batteries ASAP. If you’re lucky, there’ll be no damage to the motherboard. If you’

Even if you’re not going to restore them right away, I’d suggest removing the batteries ASAP. If you’re lucky, there’ll be no damage to the motherboard. If you’re unlucky, you can treat and stop any further corrosion by treating with white vinegar and an old toothbrush. Leave for a while then clean that with IPA (not the beer!). That’ll buy you the time to restore at your leisure.