Design & Deploy - Deleting Modules


I've inherited a bit of a mess I'm trying to unpick and clean up our setup.

I've a company administrator account (with full permissions), though some of the custom modules previous employees have published cannot be deleted (from within the Design & Deploy area).

What's the best way to remove these, please? All the user accounts seem to be company admins and I'm just not having any luck influencing objects created by other admins?!