Lay newspapers out around the cabinet. Remove all hardware from the cabinet using your screwdriver. Place painter’s tape over any non-wood parts that you can’t remove.
Load your sander with heavy sandpaper. Sand the whole wood surface of the cabinet, taking off the existing finish completely. Brush off the dust.
Re-sand the surface with fine sandpaper on the sander, smoothing out the exposed wood. Brush off the dust.
Apply wood stain over the first section of the cabinet with a paintbrush, starting at the top. Spread the stain on as thickly as you can get it to stay.
Let the stain sit for one minute. Wipe it up with rags, leaving only the stain that has soaked into the wood. Repeat for each section of the cabinet.
Let the stain set for 24 hours.
Brush on a coat of polyurethane with the paintbrush, keeping it thin and smooth. Brush it with the direction of the wood grain. Cover the whole cabinet.
Let the polyurethane set for eight hours. Lightly buff it by hand with extra-fine sandpaper to dull the shine of the polyurethane. Brush off any dust.
Brush on a second coat of polyurethane. Let it set. Buff it as before. Brush on a third coat of polyurethane. Let it set for 24 hours before reinstalling the cabinet hardware.