Retention Period / Deletion

I would like to find out if setting a retention period on a pool automatically applies it to all existing CLIPs, because our applications don't actually define a value.

We don't store the CLIP IDs either, so is it possible to then search for CLIPs which are past their retention period?

Lastly, can anything be run on Centera directly to delete said CLIPs or does the call have to be made from an external source (ie an application) to delete CLIPs one at a time?