If you want to clean up the recoverable email (or dumpster, recovery folder, recycle bin), you can run the following script to clean up that folder. The following command will make a copy of the emails in dumpster to the target mailbox.
Search-Mailbox -Identity test -SearchDumpsterOnly -TargetMailbox "Discovery Search Mailbox" -TargetFolder "test-RecoverableItems" -DeleteContent
If you are sure those emails are the ones you need to delete, then you can run the following the command
Search-Mailbox -Identity test -SearchDumpsterOnly -DeleteContent