There, they'll be taught Economics 101 (like the law of supply and demand and diminishing returns), the US Constitution (simply broken down into parts and read in plain English, without a Marxist professor to "interpret" it for them) and US History by eager teachers who actually love America. Civics would also be a good subject.
Once they show some knowledge about this country and how it works they can graduate and move on to their final destinations.
Hell, maybe we can even send some back as double agents. I'd even contribute to their salaries!
Oh, and I forgot to add (but please don’t share this publicly) that for the more stupid and hardcore Leftists...
We’re going to need some kind of Clockwork Orange type adjustment procedures. I’m thinking the “student” strapped to a gurney with something to keep their eyes open, shown pictures of Oprah Winfrey, the gals from the View, Kim Kardashian, Bill Clinton, etc, while they’re given jolts from a taser. Do this until any mention of these “celebrities” cause involuntary trembling.
Only then will they be safe to be released into the general public.