haha - yes i'm a bit of a disco junkie. With a few Whiskies in me, I basically become John Travolta.... Not a pretty sight. Speaking of which, I'm invited to a 50th in Feb and, apparently the 'theme' is Disco. Can't wait
On the 'taking out the garbage' thing - When I trained at my local PL club, I remember one of the first times I was in. I got in after everyone finished Deadlifting (could never get in early enough due to work, which is why I never kept going). I was DL'ing myself, worked up to my heaviest set and the guy that runs the club just came up and said "drop the weight down to 80 (KG) now, and do about 15 reps, nothing too difficult, just to flush out your system and make you less sore tomorrow".
Well, I was in agony for about 4 days after that. I had never done that many reps on Deadlift. Ha! So much for increased recovery. All it gave me was a John Wayne walk for the best part of a week!
Obviously this is an exception, though. At that time my general conditioning was terrible, too. So it was a shock to the system. The set didn't feel all that difficult, but the pain really shocked me. The times that i've done it after that - and I still do it quite a lot just now - It's deffinitly felt good. I find it very difficult to properly gauge how effective these things are but it does 'feel' good.
Also, I like doing 'blood work'. Say, my shoulders aching. If I go into the gym and do some high rep easy sets of external rotations, rows, push ups, etc just taking the set to the point where you BEGIN to feel fatigue, then stopping. Very light. I feel great when I do that.
I also like the light sets to play around with technique. With the beginners training with me just now, I often get them to do some 'technique work' after their heaviest/last set, and I feel it helps give them a chance to feel out the movement properly, without the risk 'ruining' a working set.
So, in short - I believe there's value in it. It's difficult to gauge exactly how much but I deffinitly think there's something in it.