I cleaned my YUGO and my Chinese with K1 kerosene took less than a Gal. to do both,other tools used small 2' wide paint brush two cheap stiff tooth brushes and my 200 psi air compressor. I took the trigger group,bolt,magazine all the springs and gas piston & short rod and let them soak while doing the receivers. Kerosene is less flammable then the other cleaners plus I reused it to burn brush piles later.
I wear some old rubber gloves coat the receiver from one end to the other and let it soak for about 15 min. Then use a combination of the two brushes to scrub it,if I come across a place I can't get into I use the high pressure air to blow it out,kerosene soften and dissolves the cosmo really well. Once it's clean I wipe it down dry and used the air to blow any remaining cleaner and gunk out of area's I can't wipe off and then applied a very light coat of oil over the entire receiver and barrel. Go ahead and clean the bore and ream the chamber out while you at this stage and do the gas port inside the gas block as well.
Next I take each individual part and do the same with them,I leave the gas piston dry once cleaned,lightly oil the trigger group and use gun grease where needed,I clean the gas tube like it were a rifle barrel using patches and a appropriate size bore brush. As far as the bolt goes I use a different method I boil mine for about 45 min. Every 15 min I grab it with some tongs and work the bolt back and forth which moves the firing pin inside the bolt,then blast it from front and back with high pressure air then back in the pot,I repeat the process about three times.
It's worked for me for the past three years with no problems each time I clean my SKS I wash the bolt down with cheap brake clean the kind that leaves no residue,I also make sure I put about 1/3 of a can through the firing pin hole and I don't and you shouldn't use any oil or grease on the firing pin area whatsoever. Some like to take the bolt apart and thats fine do what you feel most comfortable with,I shoot mostly reloads so I don't have much of a problem with my rifle getting as dirty as I would using some of the Russian ammo.
When reassembling repack the short rod and spring under the rear sight with some quality molly or gun grease I put a little gun grease or molly grease in my hand and work it into the recoil spring. leave the gas piston and inside of the tube dry unless it going into longterm storage any oil there just helps the residue build up quicker. Use your favorite gun oil and grease sparingly more is not always better it just attract more dirt. As far as the stock goes I sweated mine out in the hot sun water and chemicals aren't the best thing to use on these types of stocks that have been soaking in cosmo for 30+ years,sometime it makes the grain of the wood swell and can cause things like the trigger group not to fit back in tightly . Take your time and do it right the first time around and you will have allot more time shooting than dealing with problems.