(while (re-search-backward (concat "^" nnfolder-article-marker) nil t)
(delete-region (point) (progn (forward-line 1) (point))))
(when nnmail-cache-accepted-message-ids
(while (re-search-backward (concat "^" nnfolder-article-marker) nil t)
(delete-region (point) (progn (forward-line 1) (point))))
(when nnmail-cache-accepted-message-ids