FROM THE children and their new toys to friends and their party foolishness, your wood furniture takes quite a beating between Christmas and New Year's. Knowing the proper care for your Great Grandmother's Chippendale highboy or a new Scandinavian wood dining table is essential. Wood will last many lifetimes if treated well.

Homer Formby, antique expert and inventor/producer of both a furniture cleaner and lemon oil furniture treatment, says "furniture is the second largest investment after your home. It should be kept in the best possible condition."

Scott Odell, head conservateur at the National Museum of American History, agrees that cleaning and maintenance are important, but says that every piece of furniture is different -- 18th-century pieces differ from early American.

Cleaning & Polishing

Before touching older pieces, Odell suggests finding out the history of the piece. He also cautions that "our" approach at the Smithsonian "is not necessarily good for the homeowner. A maintenance rule of thumb is 'do less rather than more.' "

"When buying an old piece, try cleaning it first in one particularly bad area -- before refinishing," Homer Formby stresses. "Sixty percent of the time you'll find the piece won't need to be refinished."

Formby recommends oil paint thinner, mineral spirits or charcoal lighter fluid as good cleaners -- especially since most people have them around the house. "Commercial furniture cleaners have the same ingredients, but cost more," adds Formby.

Cleaning will get rid of any wax buildup that comes from polishing furniture, says Formby. "Wax buildup will make the wood darker and give it a gummy feeling. Over polishing -- particularly with oil -- attracts air pollutants. These in turn settle on your furniture. Waxing should only be done twice a year."

When waxing, always strip off the old layer first, otherwise the wood will turn darker with each layer.

According to Formby, "It's a fallacy, that wax is a protective coating. It's not. It only leaves you with a shine."

Scott Odell also says that overcleaning is dangerous. "Never clean down to the original finish," he says. "Although it may be more attractive to you, to a serious collector, the value of the piece may be greatly diminished. Think about the value of your piece to future generations. Our advice to furniture donors is always: 'don't clean it up or refinish it. We'll take it as is.' "

Once a month while dusting, says Formby, use a soft cloth with lemon oil. The oil penetrates the finish, restoring oil to the wood. The oil also dissolves daily pollution. Lemon oil won't leave the wood feeling greasy, while linseed-, silicone- or beeswax-based oil might. Read the label of commercial furniture treatments to see what the oil you use, contains. Once a year Formby suggests oiling underneath your furniture.

Odell says that if you don't use oil polishes or finishes you can dust less. He suggests a damp rag, followed by a dry one. Odell adds that, "some oils -- polishes and finishes -- are harmful. Linseed oil -- although it's widely used -- is a problem. Its quality varies immensely. No matter how much you rub it in, you cannot rub enough off. It leaves a film. It also darkens and sometimes softens wood. The often-made comment that oil polishes and finishes feed and penetrate wood is over-emphasized. When dealing with valuable antiques I'd stay away from oil in general."

For furniture made today, Paul Hutt of Bloomingdales' furniture department recommends using either an oil- or wax-based product for polishing twice a year. "But stay away from silicone products," he warns. "Silicone will seal the pores in the wood."

On the other hand, cabinetmaker Bernie Shipe of Woodward & Lothrop's furniture repair department recommends polishing or waxing once every 3 months. In between polishings, he suggests wiping the furniture with a damp cloth, followed by a dry cloth. Be sure to follow the grain when both polishing and dusting, he says.

Refinishing

If you are going to refinish, Odell says "we always recommend wax finishes -- as long as it's true wax, not wax plus costly ingredient 'X'. Wax is more likely to be safe than oil, when choosing between commercial products. The composition of oil products vary by month -- even by the same manufacturer. It pays to be more fussy with valuable pieces. At the Smithsonian we use a wax polish -- similar to paraffin wax. It give a glossy finish and is easily removed."

"And whatever you do, never strip a piece down to the original wood before refinishing," adds Odell.

Before refinishing a piece, you no longer have to strip it first, according to Formby. "Stripping wood also strips the wood of its patina, ruining its value," says Formby.

Prior to his current business, Formby ran a number of antique shops where his professional wood strippers used fine sifted sand to refinish wood furniture. They would rub the sand onto the wood surface just until the original wood showed through. "It usually took two to three weeks," recalls Formby. "As the years passed I realized that the real pros were dying off. I tried to teach the skills to young people, but out of a class of 40, only two remained. I looked into the possibility of a substance that could be applied to a wood surface and strip the wood of its old finish without the expertise these men had -- something the homeowner could do himself at a reasonable price." The result: Formby's Lemon Oil Treatment and Furniture Cleaner.

Formby suggests calling various antique shops and ask who does their work; how long they've been in business. Ask for a list of some of the refinishers' customers -- a reliable shop will be glad to give you their names.

"Stay away from dip and strip places -- where they dip your wood piece into a vat of chemicals, allow it to sit overnight and then refinish it. These chemicals expand the wood. When you apply the refinisher with a wire brush, the brush will gouge out the wood. The chemicals often tend to unglue joints in the furniture.

Alan Hall and James Heard, authors of "Wood Finishing & Refinishing" (Holt, Rinehart and Winston, 1982), say "there is no ideal finishing material. Each has some advantages and some disadvantages . . . the choice of a finish depends on the desired appearance and a balance of the properties offered by each." Oil finishes, they write, are made of a penetrating sealer and oil. They dry to a hard film and produce a flat finish. Wax finishes are a combination of stains, solvents and wax. "The idea is that the solvent will carry the wax and stain into the wood fibers. Some wax remains on the surface."

Oil and wax finishes, they conclude "are intended for amateur use and are not in the same class as shellac and other varnishes for applying fine furniture finishes."

Miscellaneous Advice

Odell also suggests you keep your wood furniture away from direct sunlight; away from direct heat such as radiators (particularly wood musical instruments); and away from moisture. "Veneer or painted wood are doubly delicate, since different parts of the structure will expand at different rates if exposed to heat or moisture. This may cause the piece to buckle or crack in spots."

Problem Solving

Formby has some uncommon solutions for common problems you may have with your wood furniture:

White rings: Homer Formby suggests dipping a cotton cloth (handkerchiefs are fine) into water. "Be sure it's cotton," warns Formby. "Manmade materials will scratch the wood." Fold the ends toward the center, so no edges face out. Squeeze toothpaste onto the wet cloth. Rub the wood with the cloth till the ring comes out -- anywhere from 2 to 10 minutes. Buff with a dry cloth.

"Toothpaste," admits Formby, "sounds unusual but you'd be surprised at its cleaning strength. I use it for lots of things -- pewter, silver, patent leather, hard leather and refrigerator door tubing."

Cigarette ashes are often suggested to get out white circles, but Formby points out that if the ashes contain any tobacco stems you can damage the wood.

Peeling veneer: Mix any white glue with water. Fill a hypodermic needle (from the drug store) with the mixture. With wax paper over the surface, insert the needle between the wood surface and the veneer and squirt in several places. The wax paper will "catch" the oozing glue. Leave clamped overnight.

Cigarette burns: Apply either fingernail polish remover or varnish remover with a Q-tip to the burn. The burn will come up into the Q-Tip. Since at the same time you are removing the varnish, you should then take a pen knife and scrape out any remainder of the burn. Then using a 50/50 combination of clear nail polish and nail polish remover, apply to the "hole". Formby says 5 to 6 coatings may be necessary.

Wood dents, holes, mars, missing veneer, chipped picture frames: Formby suggests mixing crayon colors over heat. Once you get the right color, fill in the area needing repair. Scrape off any excess dried crayon with a credit card.