I have half a dozen or more "desktop" games from the early 80's, which are single-title LED based battery powered games from Tomy and CGL. I've got Frogger, Caveman, PacMan and others:
(stock images, not my own :) )
They're currently stored in a box in the back of my garage: not the ideal environment, but it's relatively dry and the games themselves are wrapped in bubble wrap.
They haven't been powered on for probably 30+ years. They've no great monetary value, but I'd like to "boot them up" again just for nostalgia. I have a voltage-selectable PSU (most of the games are 6v or 9v): are there any precautions I should take to avoid damaging them before powering them up? Or will three decades of inactivity likely have rendered them unplayable anyway?