We have an internal webserver with wordpress installed that syndicates RSS News with FeedWordPress. Since this produces thousands of posts within a couple monthes we were looking for a plugin, that automatically deletes them again after some time (120 days).
I’ve been testing auto-delete-posts and auto-prune-posts.
The plugin is probably going to delete about 500-600 posts a day. Both plugins have produced error 500 after activation, until I found a post for auto-delete-posts, that suggests a codechange. Basically it reduces the amount of posts handeled at a time. Similar to what you do with your plugin “Mass Delete unused Tags”