WOOD FURNITURE can last for centuries, if you know how to care for it. Doris Goldstein, director of Home and Consumer Affairs for the Hardwood Institute, says, "Wood furniture is more enduring than plastic or glass -- it doesn't crack or break easily. And wood hasn't risen in price as astronomically as have plastics, which are petro-chemically based."

Proper care for hardwood furniture is essential -- if it's to last well. However, experts disagree on the best way to clean hardwood. Some claim lemon oil is best, while others prefer wax. Goldstein says that wax is better than polish."It's easier to maintain and you get better protection from a good wax job than you do with oil. A once-a-year waxing is plenty, except maybe on a frequently used piece, such as the dining room table. Then you might need to do it three or four times. And," she stresses, "always remove old wax before applying a fresh coat. Old wax can be removed with soap and a damp cloth or with a good wax solvent."

Goldstein suggests a paste or liquid wax. A typical paste wax is made up of 10 percent carnauba (a hard wax that is scraped from the leaves of a palm tree that grows in Brazil); 15 percent pure paraffin; and the rest, mineral spirits. "The more mineral spirits the mixture contains, the softer the product will be," says Goldstein. "And the more hard wax the mixture contains, the harder the polish. Which means the harder you will have to rub," she adds.

A liquid wax is composed of 5 percent carnauba, 10 to 15 percent paraffin, 10 percent mineral spirits and the rest, water. In liquid wax the water evaporates, leaving the film we know as polish. In paste wax, it's the mineral spirits that evaporate.

Robert Leiby, owner of Kenny Furniture Service in Rockville, advocates lemon oil. "Oil helps keep the finish on wood elastic, so it won't get brittle and crack.

"Ever notice the area on a door or drawer that gets touched by your hands? It may have a few fingerprints, but the wood won't be cracked due to the natural oil from your hands," says Leiby.

"With the finishes we have today," adds Leiby, whose firm is recommended by both W & J Sloane's and Woodward & Lothrop, "a lot of polishing is unnecessary. Too much polish builds up -- leaving a smeary look. A strong solvent is needed to remove it -- something that should be done by a professional unless the homeowner really knows what he's doing."

Ted Thomas, chairman of the Hardwood Institute, thinks it depends on the kind of wood you're working with. "If you're looking for a protective sheen finish, then wax is what you want. Wax looks good on walnut. Lemon oil, on the other hand, gives a satin-like finish that looks best on woods like mahogany or cherry. The Institute's brochure -- "Hardwood Furniture Care" -- says that the "wax or polish you choose should be determined by the finish and the amount of luster you desire."

Peter Danko, local Alexandria wood sculptor and furniture-maker agrees. "Wax is good for some types of wood, like walnut or oak. But be careful, some waxes tend to streak -- particularly the spray-on brands. Canned wax -- with a little elbow grease -- is what I like. And you often have your choice of color -- dark, amber or clear."

"An oil finish," says Danko, who sells only his own original pieces, "is nice but a lot of work. For a nice sheen you need to sandpaper the wood down with 400-600 grit paper and then apply the oil finish."

Danko also likes to use a lacquer polish on some of his pieces because it's clear, similar to polyurethane, and is as close to the wood's natural color as possible. "It allows you to see into the wood, instead of covering it up with a stain of some sort, which ruins wood's natural beauty."

And if you use wax, Danko recommends a light brushing of turpentine or alcohol when the wax starts to build up. Then wipe off and rewax, says Danko.

To refinish wood, Leiby of Kenny's uses a paint and varnish remover to strip the wood down. He lifts this off with a putty knife and then washes the surface off with a lacquer thinner. (Lacquer dries fast due to its high evaporation level.) Next Leiby sandpapers the wood, restains or redyes it, lacquers it and finally rubs it down with oil and fine sandpaper or steel wool. l

"The thing to remember," says Leiby "is not to mix wax and oil. Whatever your preference is, stick with it. The two are not compatible."

For everyday care, Leiby advises dusting with a clean or damp -- "not wet" -- cloth. Dust picks up easily from a lemon-oiled surface. "The problem with a wet cloth," says Leiby, "is not that water gets under any breaks there might be in the finish. The finish then loosens and lifts up the grain." To clean a wood surface, Leiby suggests a mild soap and damp cloth.

According to the Hardwood Institute's brochure, hardwood furniture should be dusted often, using a clean, soft, lint-free cloth. "Turn the cloth frequently and work with the grain of the wood. Wiping across the grain can cause tiny scratches." The brochure points out that there is grit in dust that behaves like an abrasive if allowed to accumulate on fine hardward finishes.

Tips for caring for hardwood:

1. Remove spills at once, using a blotting rather than a wiping motion.

2. Make sure that protective vinyl or rubber pads have a felt or fabric base.

3. Don't put furniture in front of a heating or cooling outlet.

4. Keep hardwood furniture out of direct sunlight -- even the toughest finish, says the brochure, can't prevent hardwood from fading if it's exposed to direct sunlight for extended periods every day.

5. Beware of silicones, which are contained in many of the "wax-as-you-dust" products on the market. "Silicones," says the brochure, "are used to increase the shine and bring out the luster of the finish. If they penetrate the finish, however, and get into the wood, the possibility of a successful refinishing is highly unlikely. The silicones interfere with the adhesive qualities of any new finish being applied."

6. For scratches or cigarette burns that have not penetrated too deeply into the finish, fill in with the same color shoe polish, iodine, wax stick or concealing wax.

7. White ring marks can be removed with a damp cloth. Brush the cloth over the marks using quick back-and-forth strokes, never allowing it to stop too long on the furniture since this can damage the finish. A paste made of cigar ashes and drops of oil can also be effective in removing the marks.