In Afghanistan I used a pressure washer and compressed on the lower. Pull out the bolt carrier group, charge hand and do the upper. Mine was always the cleanest by far. Since I'm getting one I will probably do the same thing.
Due to the talcum powder dust of the ME, using compressed air was the most effective method of cleaning all small arms.
I also have used the compressed air with excellent results. I recently had my first experience with Ultrasonic cleaning of my favorite Glock. One can never get into all the crevices within the frame so thought I would try this since they had a sale price for a cleaning ($25). Man-oh-man, it looks brand new! It's so pretty that I don't want to shoot it! LOL! I have actually looked at the cost of the unit and cleaning fluid but don't think I would get enough use out of it to justify the initial cost.
Nowadays pretty much all of my firearms are stripped and put into the solvent tank for cleaning. I bought one of the large solvent tanks from Harbor Freight just for this purpose. I use the real solvent from Safety Cleen not the "be kind to the environment" crap. Works great. After cleaning I blow the parts off with compressed air and relube.
I would seperate the lower, take the bolt out of the upper, clean the bolt by conventional means then go to town on the upper and lower with an industrial steam cleaner with the heat turned on the lowest setting. Then use the compressed air to dry it off.
Most of my Fighting Arms have some sort of coating on all internal parts to allow for some pretty harsh cleaning to be done with out damage! For the vast majority of the time, non chlorinated break clean is the preferd solvent for a good cleaning, followed by a good Blow dry with compressed air! ( I made a screw on valve and small hose that can screw to the air valve on a tire for this) works great on systems that have central inflation systems! Ironically, those same internal coatings help keep most contaminates from taking hold ( except the Moon dust) so a good blow out is usually all that is required. I make my own bore solvent out of Ammonia, Automatic transmission fluid and diesel/Jet-A, stinky stuff, but it really cleans the nasties out of the bore and gas port/gas drive tube, and good for bolts that get gassed out! I usually store it in paint cans I get at the paint supply store, brand new cans can be had for a few bucks and will keep the solvent good for years! I keep several chamber brushes around for cleaning the nasties out of the chamber end and around the gas tube, and a good carbon scraper is a must have for all semi autos, your going to get carbon build up even on piston guns, so having a good means of cleaning will take you a lot further then others! The FAL tends to plug the gas plug pretty good, I keep a few spares but also know that they need cleaned now and then! I polished my plugs which keeps the carbon build up from getting quite so bad, nothing like having to swap plugs in the middle of a good string of chootin to get the rifle back up on line!
Sounds similar to Ed's Red. I've made it for years, but now that I have the solvent tank don't use it much. +100 on polishing those plugs.
Have ya added a heater to your solvent tank? I like to heat mine to about 180 deg and let stuff soak for a while, really helps loosen stuff up and cleans with out leaving any harmful stuff behind! Used to get a good bed of coals going in an old Hemmet rim and set a can of the stuff on a hunk of chain link fence we had sitting around, same trick, especially good for cleaning muzzle brakes, and suppressors that couldn't be taken apart!
Get a bore scope or endoscope. they have them for the I phones an such . then you can see better inside. Sometimes blowing only drives dirt deeper. but blowing with a solvent usually does the job better.
I use CLP or it's equivalent, toothbushes, Qtips, and elbow grease. I have found that the main benefit is that I while cleaning the parts individually I inspect them for damage and/or serviceability. I found many beltfed weapons missing important parts like feed pawl springs or receiver pin retainers while cleaning them. You do not want the trigger/grip housing falling off a 249 while it is locked and loaded. The open bolt design means a runaway gun with a 100 or 200 round drum can be very exciting, especially inside an armored vehicle.
Don't do this. My cleaning approach still holds to the "less is more" approach. Don't ever use carbon scrapers.
Love me some Brake-Kleen. Strips away everything but hard carbon and copper fouling, almost like starting with a new rifle and everything must be lubed after. Tranny fluid and ammonia (50-50 mix) has always worked well for me eating out the copper fouling.
