When tidying up a firearm's stock you must first decide if you wish to effect a quick-fix or a full refinish. Lacquered or varnished stocks may look glossy when new, but they become a real headache when they begin to show their age and become frayed around the edges. Often the only option for a well worn finish like this is to strip back to bare wood and refinish from scratch. Oil coated stocks are generally more repairable without too much fuss. I will first deal with the five minute spruce up; being naturally lazy this is most often my personal choice.
Once again I recommend using very fine steel wool. Steelo pads are ideal, the same ones used for the washing up (although not the soapy ones), as they are already a convenient size. I use Cabot's Danish Oil as both a stock finish and reviver. It is available from any large hardware store, and a small tin goes a long way. Small scuff marks and scratches in the wood's finish will either come off or blend in if you gently rub the Danish Oil into the stock with your steel wool. Wipe off the excess before it dries and you will be amazed at how much better it will look.
Avoid this if you can. Taking a stock back to bare wood always takes twice as long as my patience lasts.
A lacquer finish may be removed in part by varnish or paint stripper. Be sure the stripper you use does not leave a sticky mess, as this can be worse than the original finish to remove. If you sand it back, always use a finer grade than you would like to, and revert to very fine wet and dry as soon as you are through the old finish. Carefully cover any checkering with masking tape. There is little to be gained by sanding all the square edges off your checkering. In my experience it is far better to leave it as it is.
In fact, the most you could ever do to checkering in the preparation stage (unless you intend having it professionally recut) is use a toothbrush with stripper to remove the lacquer, then again use a toothbrush to clean it out afterwards.
Dents in the woodwork can often be removed by placing a wet rag over the affected area and rubbing a hot iron over it. Do not expect miracles, but it can beat sanding back to below the level of the dent and leaving a ripple effect along the stock.
For the sake of wood to metal fit, as well as the butt pad (especially a solid one), you should remove as little wood as possible in preparing it. The final sanding should be done with 800 grit wet and dry, followed by a buff with steel wool.
I always seal the stock before starting any staining or oiling. This stops the pores of the grain soaking it up like a sponge. Wattyl Walnut Grain Filler is as goos as any, and again is available from any good hardware store. You will need to mix in a small amount of mineral turps until it becomes a runny paste. Rub the paste along the grain, wait five minutes, then rub it off with a clean cloth across the grain. There is a slight tint to this filler to add a little colour, so you may not be inclined to stain it further.
If its colour is still too palid for your liking, Birchwood Casey make excellent timber stains. Best of all is they are water based. Take a small amount of stain and dilute in water before applying. This will ensure you do not go too dark too soon and have to sand it back yet again.
For the final oil finish I recommend sticking with Cabot's Danish Oil, but Birchwood Casey Tru Oil will also give good results.
With a clean lint-free cloth (I use Chux cloths), apply a coat of Danish Oil over the complete stock. Wait 60-90 seconds. Wipe off with a clean, dry cloth before the oil has got too sticky. Allow to dry for 8 hours or so. Buff lightly with fine steel wool pad, and repeat the above steps a minimum of 8-10 times. This is a slow process, but well worth it in the long run.
After a few coats you will notice that the finish is matt, but its apparent depth increases with each coat. Remember, in this case more is better, your finish will improve and your woodwork will have more protection with the greater the number of layers you apply.
Should you wish for a glossy finish, don't wipe the last couple of coats off, just let them dry. You will still need to lightly buff when fully dry.
Keep your oil handy for the future, if the stock starts to deteriorate, simply touch up using the "Instant Gratification Method" above.