I don’t see any way, either in the browser or in a compatible client, to remove old news articles. I’ve used the Android news app, and feedreader and rss guard on my desktop. They allow you to remove articles older than x months, and this is global.
I have some feeds that publish several articles a day, and some that publish a few a month. If I set News to remove articles older than a month, I lose articles I haven’t read on some of these infrequent blogs. But if I set it to 6 months, the daily news sites end up with thousands of entries.
Is there any way to either manually prune feeds, or set the expiration on a feed-by-feed basis?
I use news since many years with different feeds having the same behaviour you described.
Why not using the “mark all as read” for the heavy traffic feeds?
I had users who forgot about some feeds and the database was filling up. In the end, I did some SQL queries manually (using timestamps and id’s for each feed) to clean up a bit. Unfortunately, I don’t know app programming to create a feature ;-(
The problem was that all items were new, and this just limits the number of deleted items (marked as read before eventually deleting them). My table size was between 700 MB for news items alone!