I picked up this Nikon n2020 recently. I had no idea if it worked or not. There was a lot of brightly colored corrosion in the battery compartment. I cleaned it out, put fresh batteries in it... nothing. I pulled off the bottom of the body and discovered that the corrosion was so bad it had eaten away some contact points below the battery compartment. I cleaned it up with vinegar, sanded the existing contacts and bridged them with solder and wire. I slapped it back together, put tje batteries back in, and it fired up, probably for the first time in years.
Other than the corrosion issue, the camera itself is in excellent condition, hardly a scratch on it. I'm going to burn a roll in it later this week.