Its easy enough. The hard part is deciding what finish to use. Get some nitrile gloves, they resist the chemicals in the stripper better.
Use whatever paint stripper you like. I used some stuff called Zip Strip.
1) Remove stock from gun (some people forget).
2) Apply stripper generously.
3) Use a plastic putty knife to scrape the bubbled finish off. Don't use steel, it may gouge the softened wood. If there are some hard to get to spots use a small stainless steel brush (you can get a three pack for a few bucks at ACE)
4) Reapply the stripper, some finishes are tough.
5) After you are done with the scraping, use a cloth to wipe the stock down to remove as much of the stripper as you can.
6) Wipe down the stock with mineral spirits, and allow to dry for a few hours.
7) Sand with a 220 grit sand paper. Sand lightly, some dark spots may remain, its usually not worth the effort and damage to the wood to remove them, especially if you re-staining the stock dark. Don't use steel wool on raw wood because some steel fibers may embed themselves and cause dark spots if they react with the moisture in the wood.
8 ) Stain and apply finish. If you want to you can sand lightly between coats of finish with a 400 grit paper, wiping down with mineral spirits after sanding. Sanding between coats gives a smoother finish.
I would not recommend a gloss finish, unless you are refinishing a show gun.
A satin or flat finish is more appropriate for handling a gun.
Apply Krud Kutter and wipe with paper towls. Continue as many applications until all the old oil is removed. Krud Kutter will help to swell the scratches and dings as wellas lighten the wood.
Wash (not soak) wood with Oxalic acid to lighten the wood and swell dings, scratches and remove dark spots. In very oiled areas like the near the butplate and spot weld areas a tooth brush is recommended.
Smooth the wood with fine steelwool and do not use sandpaper unless absolutely necessary on really deep scars or dings as it will possibly cause discoloration of the natural wood when applying the finish.
Tung Oil or True Oil work fine but Tung takes longer to dry between coats. True Oil will giver you a more glossy appearance than Tung Oil.
The two lower left stocks have not been refinished. All these BGS G1 stocks were black with many dings and scratches.