Hello, I have a settings model which initializes from description defaults and keeps its values as a properties dictionary. If when coding I happen to change or remove a description, when I edit and save the settings the stale description still remains in the properties dictionary. I am looking for a hook with which I can tell the Memento, to clear the old settings and write the new ones. Is there such a thing? For example if the model knew it was about to be saved to it could clear out/reset its values in anticipation. best regards Keith