So what's harsh about turpentine? Nothing at all - it's a natural wood product. Natural turpentine, of course! Not the petrochemical product that is sold as turpentine substitute!
A piece of old linen or cotton sheet dampened with natural turpentine can be used to wipe down grubby areas of woodwork, and it really fires up the grain, so that you can see how good the wood would look if it was polished. Linen is a little harder and rubs/polishes more than cotton. When surface dirt has been removed, take another clean piece of cotton/ linen, dampen it with natural turpentine, pour a couple of drops of linseed oilonto the rag, and polish it into the wood. The turpentine acts as a carrier to get the linseed oil
into the pores of the wood, so do not be surprised that you do not get an instant shine. Repeat after a couple of days, again and again. Slowly the turpentine will feed the oil into the wood and the wood will develop a fine surface. Do not be tempted to make a quick job by sloshing on the linseed oil, as this will result in a sticky surface that takes an eternity to dry out. But if you do overdo the oil, simply go over the wood with the turpentine-moistened rag again.
You can experiment with the natural turpentine/linseed oil mix until you are satisfied with the results, without any damage to the stock. But get the natural materials from a professssional paint supplier, not chemical imitations from a D-I-Y bodgers store!
And wood that is supposed to keep a stable form - like a gunstock - should NEVER be soaked through with water!
Patrick