Clean bolt exterior with toothbrush and wipe.  Every so often, flood interior and exterior with carb cleaner and blow dry with compressed air.  Drop of oil (CLP) on ejector, extractor pivot and spring, and in firing pin hole.  Wipe excess and re-install.  Grease on lugs of bolt.  Wipe off excess.

For winter, or very dusty conditions, use dry (graphite) lube.

Disassembly is seldom needed, unless and until you croak an extractor.  At that point, you WILL want the special bolt assembly/disassembly tool.  A good idea to have a spare extractor, ejector, and their springs always on hand.  GI, of course.

Quoted: Taking apart the bolt on the Carbine is a PITA if you do not have the special bolt tool to do it. I would not suggest you do it unless absolutely necessary. Make sure you when you clean the bore with solvents you invert the rifle (upside down) otherwise the solvent will go through the gas port and gunk it up. A light dab of grease on the shiney parts around the bolt, etc. is good enough. Not using grease will cause premature wear over time.

What he said.