Try this
- Agree on a small batch to review and make a temporary keep, discuss and remove list.
- Confirm who owns each item and what removal means in the specific storage system before deleting any shared copy.
A worked example
“These ten near-identical pictures can go in a review folder. Let’s each choose any we want before removing the rest.”
An invented example to adapt, not a real exchange or a script you have to follow.
Before you leave it here
Do not promise that deleting one copy removes every backup or recipient’s copy. State the action you actually took and verify the relevant storage location.