Scratches I touch up with a furniture touch up kit. It has three shades of marking pens sort of like Magic Markers. Just go over the scratch with the proper color of pen and it hides the scratch. If the stock has a varnish finish and the pen doesn't hide the damage to the varnish, you can take some Tru-Oil on a toothpick and carefully fill in the scratch after coloring it with the pen. If your stock finish is not shiny, you may have to carefully dull the scratch fill in with some 1,000 grit sandpaper or some 0000 steel wool until it matches the stock finish.
If you have a dent in the stock you can raise it with steam but you will have to remove all of the finish down to the bare wood. Then put a damp cloth on the dent and steam it with an iron until it comes out. The wood fibers are simply crushed and the steam will fill them out and cause them to swell up back to normal. But, like I say, you will have to work on bare wood. This means a re-finishing of the whole stock. If you want to do this, let me know and I will tell you how I do it and what I use.
Removing scratches from metal will depend on what the metal is. If it is brass, I just remove the scratched piece from the stock and use some emery cloth of various grades to remove the scratch followed by buffing on a buffing wheel. If it is steel, what I do will depend on what the finish is. If it is a blued surface, removing the scratch is extremely easy. Just thoroughly degrease the scratch and apply a bit of a cold blue solution called Formula 44/40. The stuff is fantastic. One touch and the scratch is gone. Wipe off the spot and re-oil it and you're done. If the surface is browned, you can do something similar but you will need to match the browning with either Birchwood-Casey's Plumn Brown or Laurel Mountain Forge browning solution. If the brown is more satin in appearance and looks more like a rust brown, the LMF will give a better repair. You degrease the area and apply a tiny bit of LMF to the scratch with a toothpick. Follow the directions just as if you were browning the whole barrel only just do it to the scratch area. It will take some time to touch up a scratch with LMF but done right, it will make the scratch invisable. If the brown looks more like a factory brown then Plum Brown may give you a better way to hide the scratch. It is faster than LMF but will not exactly match a rust brown. You will need to degrease the area and heat it to sizzling hot with a propane torch and then apply the Plum Brown to the scratch with a toothpick. I always touch up scratches with a toothpick so I keep the touch up just to the damaged area. The Plum Brown will instantly brown the scratch and then you let the barrel cool, wipe off the scratched area with a damp cloth and if the scratch is completely hidden, dry it and oil it. If the scratch is still visable, just repeat the heating and application of the Plum Brown until the scratch disappears. It usually takes only one application.
Scratches to color case hardened surfaces will require a bit of artestry and I find that the 44/40 instant blue usually does the job best.
I think that about covers scratches and dents. Gouges are a different thing altogether. Gouges are the result of wood being removed from the stock. How these are handled will depend on where the damage is and how bad it is. Any repair that involves replacing wood will never look like a new stock. No matter the degree of artestry, you just can't hide a repaired gouge. But, just like most anything there are no absolutes. I had a stock that had a chip missing from the toe. Fortunately it wasn't a big piece so I was able to carefully sand down the bottom of the stock until the chip was no longer visable. Of course, I had to sand all of the bottom of the butt of the stock to retain the lines as best as I could. I also had to file off part of the buttplate until everything matched up. To an expert eye, the stock wasn't perfect because the lines of the bottom of the stock, while nice and straight, were not like it was originally. But to the casual eye, the damage was gone just as if it had never happened. To put it bluntly, gouges are a bitch. Sometimes you can hide them by sanding the surrounding wood down to the level of the gouge but this is a rarity. Usually, they just become "character marks".
I use a wax on my stocks called Renaissance Wax. after cleanign my gun, I make sure my stock is good and clean and then I apply a very light coat of Renaissance Wax and buff it out. I also use it on all of the metal surfaces. It is great stuff. I can't recommend it highly enough. If you want to see a video on it, go to You Tube and search for "Renaissance Wax". There is a video on ther about a man who has tried many things on his guns but has found Ranaissance Wax to be the best yet.
https://www.youtube.com/watch?v=_OZagOg2Bek
If I missed something, get back to me and I will tell you what I do to fix it.
I just read Mike Brines recommendation about how to raise a dent, I think I'd give that a try before completely re-doing a stock.
