What is THE gold standard way of cleaning the MPX gas system?

[Fearless4x4]

I put seafoam in my cheapo ultrasonic cleaner that is dedicated to gun parts.  Usually works pretty well if I don't let it get too bad between cleanings. 

[GregJ]

I know this topic is fairly old, but thought it might help someone.   I have 4 sets of gas plugs/tappets that I rotate each time I clean my MPX, which is about 3-500 rounds, I try not to go longer than 500.  If I have to really wrench on the plug to move it, then it's gone too many rounds.  The dirty plug and tappet go into a small container of CLR, where it will stay for at least a week.  I dont care about the finish on these parts.  By then any carbon can be wiped off with a rag or an old tooth brush.  I will spray Gun Blaster or equivalent on the rings and blow clean with air hose.  Yearly I will replace all rings on plug and tappet, scrape the grooves clean (usually minimal gunk is in the groove), the expansion hole, inspect, etc.  At each cleaning I have a .45 bore brush with copper strands from a chore scrubber wrapped around it, in a pistol rod and chucked in a drill, use a cleaner like Hoppes or maybe Iosso on the brush to clean out the gas chamber.  Clean chamber, lugs, run bore snake through several times.  Yearly I will do a deep clean on the barrel and get it back to bare steel.  Clean/inspect bolt and extractor, replace spring about 2K, depending on how it and donut look. Spray Gun blaster in trigger, blow out with air hose, lube with Mobil 1 oil.  I have a mix of grease and Mobil 1 that has consistency of syrup, that I use liberally on BCG.

 

I've tried the sonic cleaner, too messy for me.  YMMV.