SUSIE and Tom had been planning to have Tom's boss and his wife over for dinner for over a year, but kept putting it off. "We just bought our white sofa last year. But it already looks as if the Salvation Army wouldn't haul it away!" Susie complained the other night.

"We could have a candlelight dinner -- and maybe a candlelight cocktail hour," suggested Tom.

"Or," he added, "I could be stretched out on the sofa when they arrive. If they want to sit down on the couch, I could make sure that my posterior is covering the Chablis stain left over from your birthday."

"I have it!" Susie smiled. "We'll take them out to dinner at that cute little Italian place downtown."

You don't have to take your guests out to the Cantina d'Italia when your white sofa or favorite white armchair needs cleaning. Cleaning white upholstery can be done professionally or by yourself depending on the furniture's makeup.

One suggestion when you select a piece of white upholstered furniture comes from Ellen Miller of the Association of Interior Decor Specialists (AIDS). "Buy furniture with fabric protectors, such as Scotchgard or Teflon." The display piece or material swatch at the furniture store should indicate if the piece has been treated. Both Scotchgard and Teflon keep stains on the surface of the material until you wipe them off. Stains are not absorbed into the fabric fibers.

Cleaning of white upholstered furniture differs depending on the fabric. The stitch used also affects the cleaning method. The embroidery stitch is more likely to string in cleaning, for instance.

For any color upholstery -- there is no substitute for a good monthly cleaning with the furniture attachment of your vacuum cleaner. Atmospheric soil comes in through windows and hides in the fibers of your furniture fabric. Tom Gandee, owner and president of Servicemaster here, says, "People don't clean furniture as often as they should because they don't see the dirt [in furniture] like the dust on a table. Just fluff a sofa cushion and you'll see all the dust that comes out."

Air conditioning is a help because the conditioner's filter "inhales" some of this atmospheric soil. Electrostatic cleaners filter out even more.

White furniture can be more difficult to clean than other colors since nearly everything shows.Haitian cotton, a nubby fiber very popular in the last few years, is extremely hard to clean. AIDS' spokesman Ellen Miller says that "Haitian cotton can be safely cleaned by very few people because it is an unrefined cotton that contains many impurities, such as cotton seeds and sometimes part of the stems. When plain water is spilled on Haitian cotton, the fabric turns a brown color that can only be extracted by professionals."

Scott Andrews, manager of Andrews, a Kensington cleaner, gives Haitian cotton what he calls a "browning treatment." Using professional brown-out agents, "Brown Chex" or "Rx for Browning," Andrews can usually extract the stains caused when water breaks down the cotton seeds that are still present in the Haitian cotton.

Miller remarks that "Haitian cotton has become the problem in the upholstery business in the last two or three years."

Natural fibers such as cotton and wool are absorbent and can attract more dirt than plastic materials.

Polyester and nylon are less absorbent. Olefin fabrics such as Herculon are naturally soil resistant. Herculon is also water repellent. Regular vacuuming should take care of Olefin.

White velvet, crushed velvet and velour need more than vacuuming. Scot Andrews, manager of Andrew's in Kensington, Md., suggests cleaning these materials with upholstery shampoo. Sponge the shampoo off and allow the material to dry. Velvets become crusty when they dry so Andrews suggests brushing off the "crust" with a clean hairbrush. "This will fluff up the material -- kind of like when your dog gets wet and you have to brush him down. If you don't, his hair will stay matted."

Cleaning white vinyl upholstery is simple. No vacuuming is needed, just wipe the piece down with a damp cloth. However, ink stains can be a problem with vinyl. Tom Gandee of Servicemaster says that since vinyl and ink are oil based, a mild solvent must be used so as not to ruin the oil base of your vinyl furniture. Apply it sparingly and wipe it right off, being sure to blot it until it drys. AIDS' Ellen Miller recommends spraying unscented hairspray -- one that contains no coloring agents -- on the stain. Wipe it off after one to two minutes.

To prevent permanent stains, here are some basic rules, according to AIDS:

Blot up spills immediately, using a clean white absorbent material.

Always pre-test spot removal formulas on an inconspicuous piece of fabric. K2R, Carbona and Renuzit are some of the popular brand names of spot removers that can be purchased at local hardware stores and supermarkets. Do not use flammable liquids such as carbon tetrachloride, lighter fluid or gasoline.

Work with small amounts of the formula and blot often. Don't brush or rub.

Work from the outer edge toward the center of the stain.

Be patient -- some stains take longer to remove than others.

Seek the advice of a professional cleaner if you're in doubt as to the cleaning procedure.