A few suggestions
I think you have to be more specific about your goals.
For example, if all you're trying to do is degrease the action and barrel channel, as you originally stated, then a firearms degreasing spray that is similar to brake or circuit cleaner (it's mostly light volatiles - we have several products here with the most common being GunScrubber:
http://www.cabelas.com/p-0037557227899a.shtml ) works great. All you have to do is first brush these areas out with a toothbrush and some bore cleaner (in other words something thin to losen it all up) and then hose it all out with the spray cleaner. These sprays are designed to dry almost instantly and leave behind no residue. The fluid that washes out will amaze you (it'll be brown and full of gunk) and it'll also be toxic and terrible for the environment so I would suggest having some paper towels to catch it and then burning those as the least offensive way to get rid of this stuff.
Here is a link to a brake cleaner at my friend's store (I picked UK but they have stores in Scandanavia also):
http://www.clasohlson.co.uk/Product/Product.aspx?id=137348490
That product is
very similar to GunScrubber but it is not finish or plastics safe.
This product is more similar to "polymer safe" GunScrubber but I still don't vouch for it safety regarding older finishes such as shellacs and varnishes etc.:
http://www.clasohlson.co.uk/Product/Product.aspx?id=137348148
So there, that's a lot of info about simply getting some grease out and having a dry surface that will take to resins and epoxies etc.
Now, if you don't care to save the shellac or varnish (and/or actually want to remove it) then a plain old furniture stripper will work just fine! Go to a wood working store or a hardware store and get some stripper, some scrub pads or steel wool, and have at it. A few minutes later you'll have all of it loosened up and ready to wipe off with paper towels. You'll
still need to wipe down the stock with some sort of spirit or solvent however in order to get all of the stripper off. Mineral spirits work just fine but others have recommended turpentine to be even less damaging to wood. It's pretty stinky though!
If, on the other hand, you're simply trying to get all of the cosmoline/grease out as well as clean it up, I find that unboiled (unprocessed or raw) linseed (flaxseed) oil actually works great! It's expensive, but if you really slather it on, hit any nooks and crannies with a tooth brush, and then wipe it all back off with rags you will not only lift/wash off a lot of junk (the rags will come away black or really dirty) you'll condition and preserve/protect your stock at the same time. Works
great but do bear in mind that raw linseed oil takes weeks to "dry" so your stock will weep a bit of oil for a week or so and you'll want to wipe it down with a rag daily until it stops weeping so as not to mess up your domicile.
Hope this has been helpful! I'm going to get started on a Mauser M24/47 today that I snagged from Big 5 Sporting Goods for $199 yesterday. It's pristine and looks to have a brand new bore so I'm excited to get it cleaned up and out to the range.
You've been doing this for awhile I know so I'm interested in how you get rid of the dirty (and dangerous) rags in Holland? I have a fire pit out back that I incinerate them in [POOF!] because I don't want them to catch fire in my trash or garage but I'm curious if you can do that where you live?
Best,
Oly