Durango_Boy wrote:
Really, there are only two things to worry about, the chamber in the head and the piston head face. The cylinder walls are constantly scraped and cleaned by the piston rings and the combustion itself helps keep the cylinder walls free of buildup.

The piston head faces and the combustion chamber usually get a coating of carbon, from the combustion process, but that can be resolved with a good mixture and properly set timing. engines with good mixture and timing run much cleaner.

If you are worried there is a buildup of black carbon, you can aid in it's removal two easy ways.

Spritz some water into the intake while it's running, a spray every few seconds, and it will clean out some of the built up carbon. Seafoam is also a good product, sucked in through vacuum lines, to help clean things out.