i'll tell you how i cleaned my SKS first time i got it, by the way i shoot amazing groups with it.
1. disassemble all your part (remember how hehe)
2. i put all of my steel pieces (eg: springs, rods, bolts etc) into a giant pot and boiled them for a little while, this will melt off all of the cosmoline and float to the top
3. take the parts out of water and dry them with towel, don't worry about them rusting the pieces are so hot that all of the water evaporates anyways but still try to do whatever you can to get them dry.
4. the barrel was too big to put in the pot so i just did this by hand, rags rem oil etc
5. add your rem oil nicely to every part and put them back together reapply if neccessary
6. once your gun is all put together do touch ups on cleaning, remember some of the cosmoline may be on your stock so clean that before hand
Sure there are other methods i read things such as gasoline eats up cosmoline and other things but water is free and works mighty fine. Do a good cleaning this one is most important i took my entire evening to do it, well worth it

enjoy