How do I clean engine parts with denatured alcohol?[ I just got some Den.Alc from HD]. Do I use a cloth? I just clean the external parts right- like the nozzles, Needle etc? I dont have to pour some in the piston chamber, carburettror etc? I know it sounds crazy but i'd rather ask!!

My socket screw says size 6-32, 3/4". What do these numbers denote and is this SAE?

Where can I get a long socket /hex head screw driver for this size?