Before you do anything else, it’s worth giving your piece a good clean as it probably hasn’t had one in some time. There are probably some layers of dirt and grime that have built up over the years, and you might end up finding a nice finish underneath. You should be able to get some off just using a damp microfiber cloth, but applying some white spirit to a clean, dry cloth will help with more stubborn areas. If you’re cleaning wood, make sure to wipe in the direction of the grain and make sure not to soak or saturate it.