Is it possible to unload existing chunks permanently?

As the title says, I'm looking for a way to unload chunks on a map as if it was never explored.

At some point on my server, a faction had to move far enough away from a player so they could stop being raided. Later we found out he was hacking and now we want to unload the chunks they loaded to get to their base.
As an example, our spawn is at 365 x, 216 z. The faction base eventually went as far as -18k x and around 6k z. Had I known about how much memory chunks take up, I'd have stopped them much sooner.

Any tips you can give me for removing chunks, even if it doesn't involve a plugin, would be greatly appreciated.

Cheers.

 

As soon as you restart your server, and nobody goes to these chunks, they never get loaded, and don't use any RAM whatsoever. Just some space on the hard disk.

If you really want to get rid of them, go there, use a tool like WorldEdit to find out in what region file(s) (.mca) they are, and then delete that file from your drive.

 

Is it normal that, with view distance 5 and 1 player. servr loads around 2000+ chunks.. with no one being there. and having around 2k entities? Even after I do /remove item 50000000 and all the 2k+ entities get removed. they reappear in 2-5 seconds again... slowly