solid wood or laminated surface?
If its solid wood, belt sand the top down and revarnish.
Don't belt sand it unless you want to mess the surface up - belt sanding is too aggressive for that, it's more for turning rough bumpy surfaces flat and shaping wood.
Give it a good rub down with some 120 grit or an orbital sander with some 120 and then lacquer it. I prefer nitrocellulose lacquers but that's just me.

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