How to unwatch the reserved forum

In the past whenever I clicked on the "new posts" I started getting all sort of adds related to diferent college institutions and/or universities, partially in asian fonts, which I also posted about in a couple of threads related to this issue, in this section, that got very few replies (actually only one, by another member experimenting a similar issue). I dealt with it by putting every member whom seemed to put this type of adds, in my ignore list, and it seemed to work at the time, for a short lapse of time. After a few months, this issue finished happening.

But now it has started again, although now each diferent add appears under diferent users names, where it makes it almost imposiblle to purge them all by putting those users names on my ignore list, as they keep on appearing with diferent users names, and this time it is not about college institutions or universities, but about diferent type of drugs and supplements.

This whole issue is very annoying, as about 4 to 8 of this type of posts appear in each page, after clicking on the new posts section. And my ignore list is getting bigger by the dozens each day, as each day goes by.

The only common issue between both events (had to click on some of thems, to find out from where they were) is that they appear to be from a "Reserved" forum, where all threads started there, actually get no replies. And there is no tool available there, in order to put it as unwatch, in order to avoid it from continue happening.