Slip 2000 Gas Piston Parts and Choke Tube Cleaner is wonderful for cleaning both choke tubes and Gas Pistons, typically the two things that get super dirty. Just put them in the jar, wait a few minutes, and they come our sparking clean.
For everything else on my shotgun, I use Shooter's Choice Shotgun and Choke Tube Cleaner. This just eats Carbon build-up alive:
Finally, I use a few sparing drops for Slip 2000 gun lubricant for lubrication.
