Got what I think is a pre-ban AR from a relative and he only shot it about once every couple of years and then would stash it in the closet. NO cleaning! It's got heavy fouling and carbon buildup on the the bolt and carrier. What's the BEST way to get rid of that stuff and clean it up. I've never cleaned a gun this dirty.

Want to see a picture of it before I started cleaning it? Look under the forum topic "Help Posting Pics of my Pre-Ban AR15-A2" under "General Discussion." And thanks to VA-Gunnut for posting the pic for me.
-Steel

That bad, huh?  

Drop the bolt and carrier (disassembled)
into a container full of Hoppe's and let it
soak for a few hours or a day.  That'll loosen up the crud.

You may have to soak the barrel extension area in Hoppe's as well.  You could plug the barrel and fill it with the stuff for a good soaking for an hour or two.  But some Hoppe's may get into the gas tube, in which case it would be a good idea to get that stuff out of the gas tube.

Clean the gas tube with a long pipe cleaner soaked in acetone.  No oil in the gas tube, please!  Pour a little acetone in the tube and it'll run out the gas port, cleaning the Hoppe's out of it.

CJ

Super Tech 2000 carb cleaner sold at Walmart is the best stuff for cleaning any Sweets 7.62 bore cleaner outta your gas tube or Hoppes for that matter.

Nice looking original SP1 slab-side. Good Luck.

Mike

After doing all of the above, take it outside with a container of liquid Dawn dish detergent.  Give it a good cleaning and then oil it back up.  Should be like new then.

Simple Green is good for all the general crud that isn't cooked on carbon.  Rinse & re-oil.

Carb or brake cleaner is pretty decent for the baked on craploa.  Mr. CM Johnson's recommendation is probably the best for the tough stuff.

Want to go cheap?  
Get some Gasoline, and dump the carrier in there.

 Pink solvent, C-rock, pink solvent.

Great ideas guys! But "paspecops" what is..."Pink solvent, C-rock, pink solvent"? And "Norm_G" if I use the Carb/Brake cleaner is there anything it should NOT touch on the AR as far as the action goes?
"Smoke'em if you got'em."

As a rule AR's tend to have "dirty" actions due to their design.  The gas tube directs gas from the barrel directly into the bolt carrier, so they tend to get ugly.

The good news is that because of its design, crud is "managed" by the bolt carrier.  There have been some good discussions (read: arguments) about this in the past.  I tend to fall on the side of those who say that bolt carrier crud is "self regulating".

I have secured (read: have stolen) a baking pan from the kitchen.  I use it as a parts washing bin.  I simply disassemble my bolt carrier, place the parts in the baking pan and liberally coat them with solvent.  As the pools of solvent form on the bottom of the pan you can tilt the pan and move the parts to the bottm so that they can soak in the solvent as long as they need to soak.

Then I use simply use the plastic GI cleaning brush to loosen the remaining crud.  

P.S.  One time I shot that el cheapo reloaded stuff that comes in the 50 round box, and it left a weird green residue in my weapon.  WTF?