You can buff out fine scratches using
very fine steel wool saturated with clear Danish oil. (You can also use
ultra-fine automotive rubbing compound.) The process shown here only works for
scratches in the finish itself, not scratches that are all the way into the
stain or the wood.
1.Pour a
generous amount of clear or neutral Danish oil onto a very fine steel wool pad.
Rub the surface with the oil-saturated pad using your flat hand. Rub with the
grain, never against it or at an angle to it. Continue rubbing until you remove
enough of the clear surface finish to eliminate the scratches, but be careful
not to remove any of the stain below the clear finish. Rub not only the
scratched area but also the area around it in gradually decreasing amounts. Be
careful not to rub edges or corners excessively; they wear through quickly.

Click image to enlarge.
2. Wipe away
all the danish oil with rags or paper towels, then thoroughly clean the entire
surface with mineral spirits several times to make sure all the oil is removed.
If any oil remains, the lacquer (Photo 3) won’t adhere. Allow the surface
to dry overnight before applying lacquer.
CAUTION: RAGS AND STEEL
WOOL SATURATED WITH DANISH OIL CAN SPONTANEOUSLY COMBUST IF LEFT BUNCHED UP.
DRY THEM OUTDOORS, SPREAD OUT LOOSELY. WHEN THE OIL HAS DRIED, YOU CAN SAFELY
THROW THE RAGS AND STEEL WOOL IN THE TRASH.
3. Spray the
entire surface with clear lacquer. Move the spray can in one continuous,
straight stroke, allowing the spray to extend beyond the edges in all
directions. Wipe the nozzle with a rag after each stroke to prevent drips. Move
with the grain, and make sure the angle of the spray remains the same all the
way across. Keep the spray aimed away from other surfaces that you don’t
want coated, or mask them with newspaper.