The two I owned were finished in lacquer - a very forgiving and easily touched-up finish.
What's going on? Is the finish damaged? Peeling? This job requires a bit of finesse, but is easily done as described below. This is not the time for your garnet paper & aerosols.
The only paper you should need is some wet/dry in ~800 or 1000 grit. You'll need a can of lacquer, a can of lacquer thinner, a rag, a good flat "pony" brush... maybe 8 or 10mm or so, a little block (can be any old scrap of wood,) the aforementioned paper, and a bit of polish (or no polish, if you don't mind buffing with a scrap of flannel.)
Wet your rag in lacquer thinner, and very carefully wipe off the finish in areas you wish to refinish. The lacquer thinner will dissolve the lacquer instantly, so be very careful whilst doing this. Fold your rag into a sharp corner, and pay careful attention to where you're wiping. Don't bother with tape... it won't be any help, and will only make a mess. Go over the wood a second time to ensure you've removed all the finish.
Brush some fresh lacquer over the tip. Brush right up to and slightly over (e.g. 1mm or so) the existing finish. The new lacquer will "burn" right into the old finish where you overlap, which is part of what makes it such a great finish. The margin will be invisible. Another great property of lacquer is that it dries very quickly. After 15 minutes or so, apply another coat. Repeat until you've built the finish about as high as on the rest of the stock. 3 coats will probably be about right.
Let dry for a couple of hours. Wet sand lightly with your 800 paper and block. Sand only enough to remove your brush marks and level the finish. You can always brush on more lacquer if you find your finish isn't built high enough.
Polish it out. You can use practically any polish for this. Even toothpaste on a rag will work. In fact, even a rag (e.g. a piece of flannel) by itself will work, if you have the time and inclination. If you find you have open grain ("pores") showing, you can fill them with more lacquer. You can check to see how the end result will look at any time by wetting the sanded lacquer with water or some spit.
That's to "refinish." If the finish is just marred in a few spots, you could simply brush on some more lacquer, and sand & polish.