Not a DMM, but an Anritsu 'Sitemaster' spectrum analyser. When I got it, it was still snugly in it's beautiful carry bag, complete with two software CD's and 'standard accessories'.
The original 18V 1.8Ah NiMH 'SM-Energy' made in USA custom battery was still inside the compartment. It used Panasonic cells, and, unusual for such a battery pack, a 'BMS' with its own custom IC, not to mention two thermistors for temperature reporting.
Now, the battery would not pull out from the instrument, so I parted the case halves to look inside. Attach 1. The battery had spewed so much liquid that it was wet everywhere around the case walls on both halves. The dried up disaster had to be seen to be believed.
After much vinegar, isopropyl , and elbow grease, just you look how I made all the goo go away. Attach 2-6. Damage to boards was only on just one inconsequential edge each.
The sitemaster works without battery, and it did, perfectly, on first power up.
Edit: Attach 1 has become the last, I am afraid.