The mail should be auto-deleted after the cumulative total of your spool retry time.
In your case, given the example in your original post, your total, cumulative, time is 65 minutes. This may be further delayed by SmarterMail's initial processing time, outbound spam checking, and other factors, but even taking those factors into consideration, your queue should be completely sent within 120 minutes.
If the spooled items are not being deleted after the total cumulative time, then there are other issues.
As an FYI, the IETF standard, for total cumulative retry time, is 4 days. That has not been changed since the standard was first published. This is documented in retry times settings section of my SmarterMail Antispam Settings Document
Bruce Barnes
ChicagoNetTech Inc
brucecnt@comcast.net
Phonr: (773) 491-9019
Phone: (224) 444-0169
E-Mail and DNS Security Specialist
Network Security Specialist
Customer Service Portal: https://portal.chicagonettech.com
Website: https://www.ChicagoNetTech.com
Security Blog: http://networkbastion.blogspot.com/
Web and E-Mail Hosting, E-Mail Security and Consulting