For those interested in the future, I opened a ticket with Epicor and was informed that there is no way to purge completed tasks from the CRM module, even if the quote those tasks were created from has been purged. Epicor suggested I submit an enhancement request..
We have thousands of closed tasks from the CRM module that were associated to quotes that have since been purged. While the quotes have been purged, the tasks remain. Is there a way to purge these closed tasks?