(temporarily) save data to cookie or session

[ub.ch]

Heya!

I built a plugin with a search in it, which I want to paginate.
The easiest way in my mind was to save the search term(s) either into a session or a cookie and then, when page two is requested, do the search query again.

Now I can't seem to be able to access either cookies or session.
Tried using $_SESSION or $_COOKIE or vbsetsession() but to little avail it did not work

Any recommendations on how to properly do this?

Any help is really appreciated

ps: with "not working" I mean, that I can write to either, but after reloading the page, the information is no longer saved