can I be nosey and ask how you refinished your yugo 59/66 sks? it looks great!
First you need to get ALL the cosmoline out of the wood. I did this by heating the stock in the dryer (our dryer has a rack for doing shoes and the stock just fits) and wiping it off. Repeat until no cosmo left.
Then sand down to bare wood (most SKS don't really have a finish, at least the two I have didn't) once you get the cosmo off there isn't really anything but wood left. If it's real dirty, you can clean with TSP or Murphy's oil soap. Don't want to use water if you can help it. It opens the pores in the wood.
Anyway, sanded the stock smooth making sure to leave any interesting marks (arsenal marks, s/n etc..). Probably 4 hours of sanding starting with 100 grit and ending up with 400 grit. I tried using 0000 steel wool but it seems to make the stock dirty as you sand it (oil in the steel wool??)
After it's all sanded, I applied one or two coats of stain (I used Minwax Red Sedona #222) and then probably more than 10 coats of tru-oil.
First couple coats of tru oil were applied with a rag but once you get a base, the additional very thin coats are applied with your finger/hand and rubbed into the grain.
24 hours after the last coat, waxed real good with Birtchwood Casey gun stock wax.