i hot tank greasy stocks, and it pretty much removes all the grease and grime from wood, avoid, oven cleaner, bleach, solvents ect, it tends to break the wood down,
beach and birch tends to have a lot of dark spots, and figure, could be sap, grease, or just the woods character, these are battle rifles, though i love a pretty stock, i like a stock with some history as well, i try not to remove the history, isnt that why we all love these old clunky rifles??