>OK, in the Replies section I see a button named "Default". I've never used it, don't know what it does (delete/clear them?). That's not what I would like to do.

That is the standard Default reset for each list.

>I like your Read/Unread idea better.

Yes, pretty much a little better as it would allow the management of items, thus keeping them, but once moved to Read, it does not show in the black counter.