How to delete all workspaces older than specified number of days in RPASCE?

Hi all,

Many old workspaces occupy a big amount of spaces. We would like to delete them by some OAT task or batch task, or even do it manually in Manage Workspaces.
But I don't find a way to do it in OAT or batch control. Even in Manage Workspaces, as AP_ADMIN_STAGE, I can't delete any others' workspace.
In batch control, workspace can be deleted by Template name. That will have impact on users' current work.

Is there anyway to system-wise delete old workspaces based on created time or last refresh time?
Here is system info:

RPASCE Client (JET UI)