Getting rid of Dota 2

I just noticed I still have 7 copies of Dota 2 sitting in my inventory. I've already given all of my friends who didn't have it a copy. I've heard there is an automated website which hands out as much Dota 2 as you want, so I guess nobody really needs it anymore.

So, I'm wondering, is there a way to get Dota 2 out of my inventory, since it's wothless and only clogging up space?