> What I really want is for all cookies to be deleted when the browser exits, except for the sites assigned to the containers I've created.
Then Cookie AutoDelete (CAD) is exact what you'd want. Firefox has a setting option that deletes all cookies except exception after the browser is closed. But in my opinion, that function is too limited. CAD filters domains on container level, while Firefox's doesn't. CAD also offers regex matching for domains, which is really useful. My favorite feature is greylisting everything in Default Firefox's container (using * regex for greylist).
CAD is compatible and best used with Firefox's Multi-Account Container.
Then Cookie AutoDelete (CAD) is exact what you'd want. Firefox has a setting option that deletes all cookies except exception after the browser is closed. But in my opinion, that function is too limited. CAD filters domains on container level, while Firefox's doesn't. CAD also offers regex matching for domains, which is really useful. My favorite feature is greylisting everything in Default Firefox's container (using * regex for greylist).
CAD is compatible and best used with Firefox's Multi-Account Container.
It will take a bit to learn how it works though.