Exorcism is a tool for cleaning ZODB, esp from shared, multi-tenant configurations, where functionality from retired add-ons causes troubling and sometimes conflicting dependencies. Currently this is mostly focused on removing specifically targeted directlyProvides, but is likely to expand in scope. Also, do not use the current version of this, it is very skeletal code tested only in a debug prompt, but will grow a UI for finding broken content and very carefully, with warnings and confirmations, repair or remove it.