How could this be applied to grab old satellites (of which there are, to put in in technical terms, "too damn many") out of orbit and bring them back to Earth for processing? Seems like some of the technology could be used to recycle space junk.

It's almost impossibly hard to return things to earth from GEO. Robert Heinlein famously wrote that "a circular orbit is halfway to anywhere", which means that the most energetically difficult part of a mission to the Andromeda Galaxy is getting out of earth's gravity well.

To get back into earth's gravity well from a circular orbit requires similar amounts of fuel. Getting things back to earth from low earth orbit is doable, if you have a heat shield, because you only have to dump enough velocity to start hitting the atmosphere, and atmospheric drag does the rest of the work.

But that doesn't work at GEO, because you're so high (22,000 miles as opposed to ~1,000 miles for LEO). It's very hard to get enough delta-V (read as "change in velocity", which is basically the amount of fuel you need per unit mass) -- you'd need something with as much fuel as the upper stage of the rocket you were launched on, plus you'd need a heat shield. Alternatively you could use electric propulsion, which takes a lot less fuel, but would also take, literally, a couple of years, during which time you're a hazard to navigation to anything in a lower orbit. Plus, electric thrusters of the size you'd need to do this aren't cheap either.

So we basically never do that. If you need to dispose of a derelict satellite at that altitude, it turns out to be much easier to raise its orbit by a few thousand kilometers.

So, nobody will be recycling space debris that lives at GEO any time soon, unless someone figures out how to do it in situ.