I just bought a Mosin Nagant (hex receiver because I thought it might have more value). I was thinking about just getting the cosmoline out of the stock and leaving it alone, but most methods I see will also take the old finish out of the wood. Is it even possible to have the best of both worlds (keep old finish so it keeps value, while also having no cosmoline)? If not, I will probably refinish the stock. I also wonder how much that will decrease the value! Input greatly appreciated. Thanks!

P.S. unless you know a PERFECT method, I really don't need tutorials on how to refinish stock

Mosins aren't valuable. Unless you're in it for the history, you can do what you want. There are people who will have you hanged for even talking about refinishing a Mosin no matter what condition it's in.

Sako, Tikka and some Russian Mosins are relatively valuable...

I got my dad one for Father's Day and we used diesel to clean it up.Didnt damage the stock and removed all the cosmoline.Then just oiled. Back up.

OP here, how do I post pictures?

How do you post pictures?

FIFY.  Some French Mosins are more valuable than the Russian ones - b/c all the French Mosins are antique.  Americans tend to pay more for American Mosins.

Unless the stock has a tiger stripe/blotchy finish I wouldn't hesitate to re-finish it. Most Mosin stocks were refinished at the time of rearsenal anyway.