How to mark all entries in the google.reader feed as UNREAD?

Question

Google

Guys, tell me how you can mark all items unread in the Reader.
The bottom line is that the Reader is very convenient, because when subscribing to a feed, which usually consists of 15-20 items (RSS), it also stores older entries, provided that someone has subscribed to it before. This is extremely convenient.
But there are feeds that are not news, but generally contain useful entries. And I would like to read them all from time to time. You can mark read with stars, but it's a little different.
There is a menu item in the feed control "Mark All as Read". There is no such reverse. Or is it there, but I don't know where it is?
Tell me if you know.
Thank you!

Answer 1

How to mark - I do not know. It doesn't seem to be possible at all.
But in the Settings/Preferences/Scroll Tracking settings, you can specify that the record does not automatically become "read" when scrolling. Valid, of course, for the entire Reader and not just for the selected subscription.

Answer 2

You can also ask to see all entries, not new ones (links above). But this is only to show, not to mark as unread.

Answer 3

As I understand it, you need to collect useful entries:
In Google Reader, there are several ways to do this:
1. "Mark" (yellow star). In my opinion, it is suitable for temporary marking of records.
2. "Like"
3. "Share"
4. "Add to general with a note"
Although 2-4 are socially oriented, no one bothers to use them only for themselves.
5. "Send by e-mail." Send to your address, and there you can filter as needed.
6. "Change tags". Add the desired tag and you can view the entries in the corresponding folder by selecting the "all entries" mode.
As you can see, there are enough opportunities, each has its own characteristics, and if you figure it out and set it up once, you can use it very effectively.