I've had a few hundred of the nos No.4Mk.2 rifles but have never peeled and cleaned one. I have cleaned up a few messes like that with ease. The last being an M1 rifle that had boiled linseed glopped all over it including on the metal. What a sticky mess it was! Here's how to fix it quickly and easily. Remove the wood, wash it in Dollar Store, grocery store grade clear ammonia. Wipe it off gently with a Scotchbrite/spongy pad, clean the nooks and crannies with a soft bristle toothbrush. There won't be any elbow grease needed. You'll see the mess come off almost immediately. Then rinse the wood pieces with cool water, pat dry or blow off with a compressor and set them in the sun to dry. That would take about 20 minutes here in South Carolina right now. There's no need for stain but stain if you want using an alcohol based stain. Chestnut Ridge is good if you like a reddish military tint. That being said with your rifle, I would forget the stain and just soak the freshly cleaned wood with raw linseed oil on a sponge brush. I like to warm the wood up in the sun, (the linseed tanks that were used originally were just warmed, not hot), and carefully rub it out with fine steel wool and then just by hand, mopping off excess with a blue paper shop towel. Just keep applying coats of raw linseed until it won't take any more or you're happy with the finish. You'll be amazed how fast it takes on a sheen as original if you do it this way. Three or four coats will do it. Taught to me by a real craftsman who specialized in restoring antique firearms and building Pennsylvania and other black powder rifles from scratch. The ammonia cleans the oil and grime off almost immediately, doesn't harm or discolor anything and once rinsed and dried, leaves a perfect base to start over with the finishing process. Remember to wear gloves and work outdoors with good ventilation.