I just had to show off a new product that is on the market called Scratch Match. When you scratch furniture or floors to the point of removing wood, you will need to either sand it all down and refinish, or work with colour matched putties. When you just scratch the finish and don't even get down to the stain, you can simply put a little more clear finish on the top, like with MinWax's great Wipe-On Poly.
But between these two extremes, when you scratch and the scratch has gone through the finish and removed a bit of the stain, but the damage to the wood is minor, you are really stuck trying to get some kind of colour match to the stain to be able to cover up the problem. There are pens and crayons and walnuts that can help, but finally someone came up with a genius idea -- why not use the stain that is right next to the scratch. Perfect colour match!
Scratch Match is transparent, so the same bottle works for any colour of stain. It flows through the scratch in the surface, sneaks under the finish and causes the original stain to flow into the scratch. If your scratch is not even through the top varnish, it won't get to the stain so won't work. Let it dry and put on a bit of Wipe-On Poly and you will never know it had been scratched.