Veneer doors are composed of particle board, which is then coated with thin strips of wood that give the door a solid wood appearance. You can restore the fading finish on your wood veneer doors by applying a fresh coat of stain. Before you begin, you must sand down the glossy polyurethane or varnish topcoat, or you will have problems with absorption. You must use care during this process, or you may permanently damage the surface you are trying to rejuvenate.
Remove the door knob from the wood veneer door, using a screwdriver.
Sand the wood veneer until it appears dull. Sand along with the grain of the wood, or the veneer will scratch and splinter.
Wipe sawdust from the wood veneer door with a tack cloth.
Slide plastic dust sheets underneath the door. Slide masking paper beneath the door, over the top of the plastic, and attach it using painter's tape.
Coat the sanded wood veneer door with oil-based stain, using an oil paintbrush. Wait six hours for the stained veneer to dry.
Wash the brush with white spirit.
Coat the stained wood veneer door with a polyurethane wood sealer or varnish, using the clean paintbrush. Wait four hours before touching the door.
Do not sand against the wood grain, or the veneer will splinter. Don't apply stain until you have sanded, or the finish will flake.