cable connector cleaner/contact enhancer

I've gone through a couple bottles of Kontak over the years.  Like it, works great, but is just too expensive.  Caig DeOxit D5 cleans just as well at a fraction of the cost.  Alcohol can be used (although the D5 is far more effective), but stay away from rubbing alcohol which typically contains lanolin and/or other skin softeners that will leave a film.  Use a 95% or higher purity isopropyl alcohol instead.

Geoff,

I haven't gone to the length of cleaning all the outlets in the house, but I did get a nice improvement with just the outlets on the same breaker circuit as the audio system.  Rather than cleaning them though, I replaced the non-system outlets with spec-grade outlets, and the difference was quite noticeable.  Not sure if it was due to dirt/oxidation, or due to the crappy contractor-grade outlets with the Romex shoved into the spring clip terminals in the back.  I stripped down to fresh Romex and tightly wrapped the wire around the screw terminals of the new outlets as it SHOULD be done.  I attributed the improvement to the fresh copper and proper mechanical fastening, but dirt and resultant arcing certainly could have been a factor as well.  Took a little time, but didn't cost much and the result was well worth it.