A storage management scheme is described that supports the invalidation of addresses to freed storage and thus, in that sense, provides a secure system. Unlike previous virtual memory techniques, the allocated areas of our scheme can vary from the very large, requiring multiple pages of storage, to the very small, in which several can be contained on a single page. Special treatment is accorded procedure activation storage so as to provide increased effectiveness for this important case. The interaction of this deletion scheme with garbage collection techniques is also examined. Finally, the relative advantages of retention and deletion strategies of storage management are considered.