Oh yes - from an early recommendation on this thread, I should also mention that I got some DeOxit Gold Cleaner (it came with a free sample of the Conditioner, which supposedly maintains the cleanliness).
First try was on the crappy original AC cord to my Garrrard turntable. This was almost a joke, but it was definitely the oldest and most corroded plug in my system. When we plugged it back in (and played the same piece), my audiophile friend and I virtually leapt out of our seats - the improvement was so marked! Improved bass transients, better resolution, sweeter highs - and this was only on an AC cord turning the turntable motor! Really our first reaction was being more drawn into the music (Enrico Mainardi playing a Tartini cello concerto), and then we dissected the details.
A smoothly turning turntable motor really is an important thing!
Next try was on the AC pins of the Io's power supply. The change here was much less marked, but I guess the pins were much cleaner (and newer).
More results as I gradually clean stuff. I don't have any other contacts with visible oxidation, so that turntable motor cord might have been the big winner.
Patrick