saving/archiving received messages (esp. emails)

[Sven Hartenstein]

Hi, 

I use nnfolder for mails and want to get one archive group for each
month with all sent and received (only those that I want to keep of
course) articles (one group for both mail AND news I think).

My ~/.gnus contains
   (setq gnus-message-archive-group
         '((concat "mail-" (format-time-string "%Y-%m"))))
which works perfectly for sent mail.

(Question 1) how can I / do I want to save received mail in the same
file? More precisely: how do I do it without hitting B m and selecting
the nnfolder by hand? Am I right, that I want to "move", not "save" the
articles? Is this a bad idea and I should rather save my messages in a
different way for any reason? How do real gnusists do it? :-)

(Question 2) I would like to automatically delete all attachments from
articles both for sent ones and for those that I save/move as mentioned
above. How can I achieve this?

(Question 3) If I have (setq gnus-total-expirable-newsgroups ".*") in my
~/.gnus, does this mean that archive groups and drafts will expire as
well? How should I change that? I would like archive and draft groups to
never expire, and all others to expire without having to change my
~/.gnus whenever I have new groups.

Any help appreciated!

Sven