This has been posted but never answered so I'll try again.
I have 250+ sites that have about 5 workflows each that need to be deleted as they are no longer in use.
I have scripted out a process that looks for a named workflow and a named list and if there are any running instances of that workflow it cancels them, then uses "workflowAssociations.Remove" to remove that association from the list (or site for site workfows). THey still show up in the Site Worklfow Inventory. The next goal is remove them from the site inventory. Is this only possible via the WorkflowGallery.aspx page? Doubtful but..any ideas?