smiddy3:
Documents go along with Records Management Video posted previously. If a record is found or even a note that could damage the Watchtower, the Certificate Of Destruction is used.
The other slip is for Retention of a record that may need to go into the Watchtower Archive. Once a record goes into the Archive it is to be kept permanently. Watchtower admits they are using outside sources or "worldly" non-Watchtower publications for research and references. (See Retention Schedule Sample Reference S at bottom.)
Try this:
https://www.docdroid.net/kKqrX6l/2018-certificate-of-destruction.pdf
Atlantis!