what is the best way to clean off the hardened carbon deposits inside the bolt carrier. it appears to be chrome lined on the inside

It is chrome lined. For the most part what CLP does not remove I would not worry about.

Only easy way I know of would be to soak the parts in something like bm12 chem tool, or slip 2000 carbon cutter.

A couple of quick turns with a M1 Garand chamber brush will make it look like new.

I can't stand leaving it in there.  I use the dental tools and Q-tips with Hoppes.

The easy way is to use a Mark Brown tool <http://www.brownells.com/aspx/NS/store/ProductDetail.aspx?p=1851&title=AR-15%2fM16+TOOLS>.  The gas Tube Wrench is also very useful.

I will give you 2 very simple ways to remove the carbon inside your BC.

1st, the cheapest -- Get a brass dremel cup brush and slightly close the bristles.  Now, chuck the brush in a variable speed drill so that the shank is only about 1/8 inch into the chuck.  Run the cup brush into the BC and give the drill a couple of slow spins.  Walla -- clean as new.



2nd, the best -- Get a ultrasonic cleaner and give it 1~10 minutes in a solution of 40% white vinegar and 60% distilled water.  The ultrasonic cleaner will have your BC CLEANER than when you first purchased your rifle.  No joke.  Just BE SURE to oil it right after you dry it because the ultrasonic cleaner removes everything.  Even inside your gas key will be cleaner than new.

I hate that part!

First


Bushmaster Bolt Carrier Scraper (field version)

Then


Glock OEM brush

First thing I do after the range is disassemble my bolt and carrier and drop it in a 50/50 solution of Hoppes #9 and turpentine.  I clean the rest of the rifle while those parts soak. This softens the carbon to the point that a combination of q-tips, patches and a old bore brush can get 95% of the deposits out.  I also made my own carbon scraper tool out of an old aluminum cleaning rod section. Since the carbon build up in this area is self-limiting (to an extent) I don’t fret it too much.