What’s your favorite cleaning method for connections

Detoxit. I have several bottles. As far as frequency, I think about doing it every few months. 

Same as @ghdprentice 

Also, inside receptacles, if you suspect an issue, use Deoxit on a lint free swab like these (link 1 or link 2) that are available in different sizes. Turn power off first.

Finally, for really corroded, inaccessible internal connections (switches, etc.), one manufacturer I know uses a good spray of D-series Deoxit (although other contact cleaners probably work too). Let it completely dry b4 using.

After trying a few over the years, I use no final coatings stronger or thicker  than Deoxit G100L (Pro Gold).

Kontack …..no longer for sale in US go online and look for it as it does not leave any residue . 

@ghdprentice 

"Detoxit"

@mitch2 

"Same as @ghdprentice"

Ah, so you're both embalmers.

Deoxit is great.

A good substitute is Isopropyl Alcohol, readily available at pharmacies.

I also use a scouring pad (not steel wool) to remove oxidation (tarnishing), especially from silver connections.

A very simple thing to do is to simply rotate the jack in its plug back and forth a few times, although this technique is not as reliable as the others mentioned.

Balanced connections are a bit more difficult, but the above methods are still effective,