After reading this story about the Beagle 2 probe found on Mars, I couldn’t help but wonder two things:
There’s been a number of different solutions proposed, including automated robots, but AFAIK, no one’s tried anything as of yet. Some of the items, like spent boosters, are easy to find/avoid, others, like paint chips (which are travelling at tens of thousands of miles an hour) are more difficult.
No wonder ETs frequent trailer parks, given their first impression the average Villa Des Pine must seem like the pinnacle of Earth civilization 
One of the most spectacular things I’ve seen was a piece of space junk come through the atmosphere on its way to crashing into the ocean.
One night I was on a small island in the Philippines (Boca Cay) just sitting on the beach looking at the stars. (I was not stoned.) Suddenly from the right I saw a colorful mix of red and green rotating across the sky. It was close enough that I could actually see it was some kind of object, not a meteor. It looked like a cylinder of some sort. It appeared and was gone in just a few seconds. I didn’t see it crash into the ocean, but I’m pretty sure that’s where it ended up.
No one was with me at the time and the people I talked to after-wards thought I was crazy, but fortunately the fisherman who fish offshore every night saw it and I was vindicated.
I bet that if you post the details here, someone’ll will be able to figure out what is was that you saw.
Orbital debris is a problem for anything new launched from earth. There are measures taken to prevent crap coming off launch vehicles, and when satellites themselves are no longer useful, they can be moved to a disposal orbit, or use some rather interesting devices to be deorbited.
If you’re asking about stuff landed on other planets proper, we’re talking about one device the size of your car or less. I’d worry way more about who’s going to clear away that when you’re done with it.
Has that terminator tether device ever actually been deployed on a real satellite? It seems like a potential single point of failure - i.e. if it activates prematurely. It also seems like a bit of an uncontrolled method of deorbiting something - I would have thought its effect was too gradual and variable to be able to use it with any kind of certainty as to where the satellite will eventually re-enter.
As of a year ago they were still in the design phase. And I doubt that pin point accuracy is really needed, since your average bird will probably almost completely burn up in the atmosphere. In fact, you could probably design the sucker so that no matter how big it was almost all of it would burn up, now that I think about it. You’d just have work out what speeds you wanted it to reenter at, and know what’s going to break off when.