That's a loaded question. I DEFINITELY have found some that should have been in the trash and I have also found some that I threw in the trash. Does that count?
I have been given a game twice now after talking with someone on the phone saying "I'm ready to throw this in the trash right now" and I convinced the person on the other end to wait until I drive over to get the machines for free. That's pretty damn close to being in the trash.
One time it was a bar that a friend of mine was hired to tear down. There were games in it still!
The second time someone called me and asked if I fix old pinball games and was wanting to just give the game to a good home or "they were taking it to the curb tomorrow morning". It was an old EM but after 10 hours of messing with it and cleaning it up, I did get it working and sold it for $400. More of a pay it forward in that situation. I certainly saved that one if I have ever "saved" one.