Here's the NVRAM chip in my miter box getting its cap split open.
The bottom half or so of this package contains the actual NVRAM circuit chip, and the top half is divided into resin-filled cavities holding a battery and a quartz crystal. We're going to completely remove the part with the battery.
The idea is to saw through the top of the package at its centerline to the top of the carrier (which is about where the battery compartment stops and the chip starts).