[pdbreen]

I flush mine with a water-alcohol solution usually in the 3.5% - 7% range pretty much on a daily basis.

I've got to try that!!

Roughly every other keg, I'll run oxiclean/pbw through the lines.  I was doing the first cleaning of 8 retired soda kegs yesterday, so was running a lot of oxiclean through the lines when I was pressure testing the rebuilt kegs.

[halenrush]

Oxyclean and starsan between every keg.  No problems so far (except this week when I dryhopped without anything to screen the hops) but now you all have me wondering.   

[dan1076]

I run star san through it every keg.  I have never taken the faucets apart and have kegged with these faucets 2+ years.

[central_wa_brewing]

I run soap water through the lines between kegs but spray a vodka/water mix up the faucet if beer is not drawn for a few days.

[wilypig]

Pretty much the same as everyone else
PBW after every keg - 5 Gallons hot
Rinse - 5 gallons hot
Star-san 5 gallons
double rinse - 5 gallons

I completely broke down my system a couple of months ago to get rid of a union in the system (leak point). I chose this time to do it due to the 'stuff' I saw in the line. I will break it down again after the keg of natural cider that is on tap now just in case.