I lot of people have their own way to clean off cosmoline but here is what I used.
1. Lots of non-chlorinated brake cleaner.
2. CLP
3. Very hot water. Yup...hot water
Disclaimer: You may not want to do this with Spoues's/Lifemate's/roommate's pots and pans. At least don't get caught
Seriously, I strongly recommend using pots and pans that will never be used for food again.
Try to remove as much cosmoline as you can with break cleaner
Take a big pot and fill it. Bring to a boil. Pour into a flat cake or casserole pan (recommend Pyrex...easier to clean up afterwards).
Drop in recoil spring you pulled out of the bolt carrier, bolt carrier, bolt, trigger group, and any other parts that will fit. You may not want to do all at once. The pan is going to get messy.
Let the parts soak. you will see the cosmoline melt off and float.
Swish around and remove. (CAUTION: PARTS ARE HOT!!).
Spray down again with break cleaner and try to remove any remaining cosmoline.
Coat parts with favorite CLP/gun oil.
The rest of the rifle is simply a lot of elbow grease, rags, and solvent/break cleaner/CLP. Be sure to get the entire gas system cleaned out. There is an operating rod (right term?) and spring under the sight. The lever used to release the gas tube also releases the op-rod. Keep rotating the lever and it will come out. Be careful not to launch it across the yard or at pets. This part gets overlooked and will cause the rifle to fail if not cleaned out.
The bolt is the hard part. The firing pin channel must be clean to allow the firing pin to free-float. If not properly cleaned out you are risking the firing pin to stick and cause slam fires. Best test is to shake the bolt and hear the firing pin rattle around.
The best thing to do is remove the firing pin. You have to use a steel punch and a big %#$@ hammer on a steady surface to punch out the retaining pin. It also holds the extractor to the bolt so be careful not to lose the spring. Once it is out, clean out the channel and reassemble. The retaining pin is a bear to get out. Don’t be afraid to pound on it. Do not spray oil back into the firing pin channel. You don't want it to get gunked up again.
Clean cosmoline covered pans and hide away to be used for next SKS.
Other people may have better suggestions for you, but this worked for me.
Rexrider