Cylinder head carbon forrest

[joel5150]

71 C10 with a 307. Removed my valve covers and see a lot of carbon and muck built up around the valves and rods. To the point where the head bolts are all buried up past half their head height. I've done some "research" (I use the term loosely) I have found quite a few instances where it is suggested not to do a flush or treatment because a chunk of carbon could get stuck in the valve, jamming it in the open position. So my question is;

Anyone on here have any experience doing a flush, or have any other suggestions on how to clean it? How common is it to have a valve stuck after doing a flush?

She does run. Leave it till it breaks? LOL. Any way to clean it out without taking the head off the motor or did I just go full tard with that question?