The answer is probably in the forum somewhere but for the life of me I couldn't dig it up!
What solvent should I soak/treat a stock and forend with to remove a well soaked in boiled linseed oil finish? I'm wanting to go back with a more waterproof finish on my Beretta S57E.
Can I expect to get the wood back to its original appearance?(ie: lighter color)......it has turned really dark from the BLO. Suggestions much appreciated!

I'll state up front for the record, that I've only ever done one stock. I have however done a lot of high end furniture restorations and refinishes.
Mineral spirits, or turpentine, followed by lacquer thinner. Don't let any of them soak. If you want to use acetone, or naptha to remove the trace petrochemical residue left over by the turpentine and lacquer thinner, feel free.
The BLO will break down and continue to "express" itself out of the pores of the wood. A BLO finish does soak in a few microns if done properly, and that's why it takes time to remove it all. Expect about a week of wiping.
Don't go nuts and try to speed the process up with steel wool, or a 3M pad. Microtek cloth will do everything you need to do.
At the end, the process will have "raised" the grain along the flatsawn lines. For this, there are 3M sponges to knock the "hairs" down. The yellow is 320 grit. The rest will need to be ordered. They go in descending order to 1500 grit. 400-600 should be fine. Don't use anything coarser than 320 grit.
Use an acid brush to apply the petrochemical products to the checkering and scrub with a new tooth brush. Don't run the sanding sponges over the checkering.
Depending upon the finish you are going to apply, an Acetone wipe, followed by an alcohol wipe may be necessary at the end, prior to knocking down the grain. The alcohol can also be used to raise the grain.
An oil based finish will be fine, but if you want to apply a water based finish, the wood will have to cleansed of all petrochemical by product. Right now, some of these products are not easy to come by. Especially the correct type of alcohol.
Time is your friend. Most people do poor finish jobs because they don't want to take the time required. Give yourself a 5-7 days to remove the finish, and an equal amount to time to apply the new one, and you can lay down a very professional finish that will last decades.
It takes me a week to apply an oil finish. Doesn't matter if it's a small jewelry box, or a large cabinet.

BLO cured is a dried varnish. I think Citri Strip would be appropriate. I sorta doubt if you are going to remove much of the darkening. But I do not know that for sure. I have never tried to remove a BLO finish.

On the stocks I have done, acetone was the answer to remove the oil stained areas but I first stripped the BLO with Citri Strip. If after using acetone soaked cloths and repeatedly removing the oils that are brought out it is still darkened; the easiest solution is to stain the wood just enough to blend those spots in with rest of stock.

Good luck!

I don't believe the BLO was what darkened the wood. When I'm finishing a stock, either new or a refinishing job, I use the sanded in oil finish taught by custom stock maker John Vest in gunsmithing classes. The initial process is saturating the wood with the oil finish of choice and John had us do the initial saturation with BLO thinned 5:1 with painters naphtha to get a rich, golden tone in the wood before transitioning to Truoil. The BLO did not darken the wood in the least. Any darkening must be from stain.



Turkish walnut stock set finished as stated above with the initial saturation done with BLO. No darkening whatsoever.

Thanks for all the differing viewpoints, guys!
The history of my stock: It was stripped of all original finish (whatever Beretta used circa 1970's)...sanded appropriately and many, many coats of BLO applied (NO STAIN was used). (Its original color was a medium golden brown similar to the old Browning stocks). The BLO immediately turned the walnut a deep chocolate tone with streaks of lighter browns....very striking contrast. (black walnut, maybe?)
My OP was primarily to assess if I could reverse things and re-capture the stocks original hue.
Prior to your responses, I had soaked the stock in acetone two times for a period of 8 hours each time. It appears that the oil has been removed, but the darker wood color seems to be permanent. Laying the stock out in the sun doesn't precipitate any oils to come to the surface, so I feel confident its pretty well removed.
My plans are to move forward with prep work and apply a tung oil finish. I believe with the contrasting grains, it will be gorgeous, even if it's fairly dark. I can live with that.
Thanks to all of you for offering up your experiences!