slant six head gasket help!!

Alright so iv got a 1972 dodge dart, 225 slant six.
Im replacing the head gasket and have the head off (done correctly) but my question is how/should I clean the head, block surface, and combustion chambers? the head still has the valves in it. push rods are out and so are the rocker arms.
Iv never done a head gasket change on a vehicle that's been "used"...
I know what to do just making sure nothings different sense the engine I did it on in shop class was a Izuzu v6 straight from the factory with no miles or dirt...:wack:
thanks