Hoppes, gun toothbrush, Q-tips, dental pick. (Brake cleaner works good too.) Not aware of a procedure, just apply the solvent, let it sit a few and clean it up.
Here's a thread I started on the subject of cleaning tools. In particular, I think you'll find the C.A.T. M4 tool, the Talon Lug tool, and the AR chamber brush interesting.
I soak the bolt in M-Pro 7 while I clean the upper and lower. After 15-20 minutes soaking I scrub it with a bronze brush. I finish off the bolt tail with a piece of green scotch brite pad soaked in cleaning solution.
Hoppe's #9, toothbrush, Q tips, rag.
I just bought a bottle of corrosionX which I just started to use it as lube after the hoppe's, but I hear it works as an awesome cleaner too, so my next cleaning will just be corrosionX, to clean and lube.
The tactical tolerance tools listed in JaPes link work wonders. I picked up both the CAT M4 and the Talon on his recommendation and they did wonders on my BCG. A little pricey, but they make the job so much easier.
Soak it in Some Ed's Red (Recipe on the Web) take it out and brush off all the carbon. Re-Lube and assemble. You don't need to buy special tools. Waste of money and all my BCG's are spotless.
Carb cleaner and break cleaner require good ventilation and orderless mineral spirits won't have your wife asking "what stinks" and giving you the evil eye for stinking up "her" house.
M4carbine.net has a good cleaning/soaking method using CLP and a orderless mineral spirits mixture.
Saw a you tube vid where the guy sprayed the parts(after disassembly) with Simple Green, let them set for about 5 minutes, took a tooth brush to them, rinsed & dried them off and used frog lube. That Simple Green cuts through just about everything, but don't use it on aluminum. However, I'm pretty sure that BCG's aren't AL.
Not GumOut, but I did use SeaFoam once. I filled a smaller pickle jar with SeaFoam, disassembled the bolt (to remove the rubber O-ring under the extractor), and put the parts in the jar, and let it sit.
Seafoam worked. I still prefer the CAT M4 tool. It's faster & doesn't stink.
I have a had a product setting around for some time and finally tried it. Shooters Choice MC#7. Wet bore and bolt parts ,let site for 10 minutes and way amassed how well it cleaned everthing up with just nylon brushes. Think for the first time in many years I have found a new product to me that works well.MC #7 Bore Cleaner and Conditioner | Shooters Choice