If you're concerned about condensation buildup rusing out the tank, take
a look at
http://www.harborfreight.com/automatic-compressor-drain-kit-46960.html


Yeah, I installed this on my 25 gallon cheapie compressor. It worked
for about a week, then one day the outlet got stuck, maybe something
stuck in it. I was futzing with it when it just crumbled. You get what
you pay for at HF.

I just wired up the tank with a 4' hose coming from the bottom with a
standard air gun on the end and I just air it it out whenever I am
over on that area of the shop. In the summer here in california I
never see any mist but get a good spray during cold weather.