Hoppe's #9 doesn't dissolve carbon very well

[Bang]

Submersed a .30 carbine bolt in Hoppe's overnight, expecting some discoloration the following day. Thought it would save disassembling the bolt.
Nope. Ran Q-Tip on face, got blackened. Pretty obvious the extractor was retaining carbon. It's the reason I bought the bolt tool.

Maybe Carb cleaner spray? I have an air compressor. Anyone have success with carbon-cutting fluids?

[Walleye Hunter]

My go-to for tough dirts is Methyl Ethyl Ketone (MEK) if you can find it anymore. I made my last purchase at Sherwin-Williams not too long about but I wouldn't be surprised if it's no longer available. It's really nasty stuff and only use it outdoors or in extremely well ventilated garage. Lowe's et al sell MEK substitute but I can assure you it does not work as well.

ETA: I cannot vouch for it's effectiveness on carbon but would expect it to work.

[frankski]

I’ve had great results using Gun Scrubber. I use it OUTSIDE. Blast the bolt, slide, insides of the receiver, whatever. Hit it with air compressor or just a can of compressed air. Let it drip dry. Very effective and fast.

[snuffy19608]

Carb cleaner, brake cleaner, Gun Scrubber if it's what I think it is will clean everything off your parts really fast. The problem is, when your parts dry right away and look dry, they ARE dry because all the oil is gone.

Metal without oil rusts, FAST. I use brake cleaner occasionally on really filthy stuff, but have a can of CLP or other oil right next to me. As soon as the solvent is gone, spray the crap out of the parts and get oil back into the pores. As long as you oil right away, you should be fine.

[Gunsnwater]

Oil of wintergreen is the carbon solvent. Marvel mystery oil has it. You can buy it straight. Be carful. It metabolizes into aspirin. It’s in Ben gay, tiger balm, gum, all kinds of stuff. Look it up.

You are asking number 9 to remove carbon without mechanical action. Not gonna happen. Get an ultrasonic cleaner. Use elbow grease.

[ideaman]

How about alcohol?