Today, I noticed some corrosion on my 93' battery tray, so I took the battery and tray out.
To my surprise, there was corrosion under the tray that was so extensive that it had rusted a hole in the shelf and I could see all the way through to the driveway. This, in turn, allowed water to enter when driving in rain causing even more rust.
Tomorrow, I plan to use a wire brush and rust inhibitor to stop the rust, then look for a way to seal the shelf area and stop the water intrusion. I may have to take it to a body shop for this.