Little black spots in wood. How do I get rid of them?

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This beech front handguard for a Lee-Enfield No1 MkIII was generously donated to me to help with a restoration. It is in very good shape, but upon stripping and cleaning it in preparation for refinishing, I uncovered a number of little black spots covering the surface. None of them are very large, nor is the handguard unsightly to my eyes, but the rest of the wood on my rifle does not have the same 'features', hence, hard to match. Here's a pic of the handguard next to the rest of the stock set, to show you want I mean:

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I am given to understand that these spots are caused by little bumps and dings that have allowed cosmoline to penetrate the wood, which then turned that spot black for reasons that seem unclear to me-- I was under the impression that cosmoline penetrates the wood in any event; were this the culprit almost all milsurp stocks would be pitch black in their entirety. I have tried a number of recipes gleaned from internet searches, including bleach, oaxalic acid, mineral spirits, wood soap, and baking in the oven as high as I dared. The result of all these antics was a small reduction in the size and appearance of the spots, but not to my satisfaction. Hence, I humbly turn to the refinishing and gunsmithing gurus and ask: What are these little bastards, and how the hell do I get rid of them?

I've had these on a number of rifles, and while lately I just leave them, I've previously removed them with a combination of thorough stripping with "paint stripper/varnish remover" and then aggressive scrubbing with steel wool and acetone.
Having said that if I was trying to clean that guard up to look like new I'd be tempted to give it some with a cabinet scraper and then sand through the grades to 320 grit. The reason being that now I like to avoid "paint stripper".

They appear to be the remains of bruising that has either been sanded or steamed out, I could suggest steaming again, but I remember copping a fair bit of abuse for some of my timber treatments on this very forum.

You mentioned bleach. Was is standard bleach or wood bleach? I've used wood bleach to remove spots and it works pretty well. It also removes rust stains. May take three applications and it doesn't always look like it's working until after it is completely dry.

Thanks to everyone who responded!

tbonesmith-- The stains seem to go well into the wood, possibly a 1/16th of an inch or more. I'm afraid scraping/sanding/wooling would remove more material than I would be comfortable with. However, I've tried every solvent except acetone. I will try that next, and thanks for the suggestion!

muffet-- I think the steaming may prove to be the ticket. The spots react most positively to heat, and as steam carries quite a load of heat energy it may prove to be enough. From a physics standpoint, what I'm looking for is enough heat to "bubble out" the spots (which was the response of the spots in some of the other "heat treatments" I tried) but not so much heat as to scorch the wood (which I came perilously close to doing). Somewhere between 250 °F and 400 °F is the range, I think, but I'm just not sure what I can get away with... and am (understandably) a little reticent to experiment too much!

Aragorn-- The oxalic acid I mentioned is technically a type of wood bleach-- if you look at the label of most wood bleach packages, it will be some percentage of oxalic acid. I got the oxalic acid specifically because I had an idea that the numerous spots were caused by bits of steel wool imbedded in the wood from a previous finisher. Iron, when allowed to oxidize in the presence of wood tannins, will form a black stain like the kind you see on wood furniture from water stains (tap water often contains trace amounts of dissolved iron). Oxalic acid is renowned for removing exactly this kind of stain... but no dice in my case. I think the stains are some kind of grease or oil rather than iron stains.

Again, thank you all for taking the time to help. Now that I've had to contend with these darned spots once, I'm seeing them everywhere, on every milsurp rifle I own or handle! If I figure out the trick to banishing them for good, I'll be sure to post the trick.

OUT, DAMNED SPOT!

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??

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Originally Posted by chuckindenver

i hot tank greasy stocks, and it pretty much removes all the grease and grime from wood,

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"hot tank"? More information, please!

Yeah, I'd like to know what a "hot tank" consists of as well!

As for the 'character spots', I don't mind them at all on my milsurps if they're come by honestly (re: during service), original to the rifle, and add to the interest of the piece. Hell, I think they're attractive! The problem in this instance is that I'm not sure where these spots come from, the handguard itself is not original to the rifle, and the marks are downright distracting and out-of-place compared to the rest of the wood. They gotta go!

The dark spots are actually dirt/oil absorbed into the damaged surface when the timber was bruised. In order to remove the dirt you need to raise the pores of the crushed/damaged area.
Only steam will do this, and if used with a detergent, will remove the marks, at the same time allowing what little elasticity left in the timber to straighten, if the damage is old, the timber can only lift slightly, but usually enough to allow the pores to open.
This envariably leaves you with raised pores and a slightly rough surface than can be smoothed by normal means, then clean linseed oil will need to be applied to bring the whitened timbers colour back to normal.
Good luck.

muffett--

I actually tried a technique very close to what you just described today. The detergent I used was a combination of wood oil soap and dish soap; the steam was provided by a pressure cooker with a few cups of distilled water in it (and some sidelong looks from the wife). After this process, it was necessary to clamp the handguard to a flat surface and allow it to dry do correct/prevent warping.

The result was a greatly diminished appearance of all of the spots, with some of them gone completely. The handguard is now hanging in my garage with a coat of raw linseed oil on it. I'll have befor/after pics as soon as possible, and thanks to everyone for their help.