REMOVING spots and stains from fabric - whether clothing, upholstered furniture, curtains or other fabrics - can often be accomplished with simple home methods.

Even if you can't get all of the stain out, in most cases you can at least remove most of it and keep the stain from setting so badly that even a professional cleaner will not be able to remove it.

Probably the single most important point in removing any fabric stain is tackling the job as soon as possible. The quicker you can remove the stain, the better the chances of preventing a spot from forming and the less chance there is of the stain's setting in the fabric.

Start by first blotting up the smear and scraping off any excess substance left on the surface. Use clean white paper towels or a white absorbent cloth for this, and do not rub over the stained area. Rubbing only helps to spread the stain and may force it deeper into the fabric. Blot lightly, and keep turning the cloth or paper towel as soon as it gets even slightly discolored.

When no more can be blotted up, the next step is to try to get the spot out with solvent or cleaning solution. This does not mean simply rubbing over the stained area. Applying solvent or cleaning fluid will loosen or dissolve the substance causing the stain, if you are using the right solvent, but unless the fluid is promptly drawn out of the fabric, the stain may just spread.

When you can reach the back side of the fabric, this can be accomplished by holding a pad of clean absorbent cloth or several thicknesses of white paper towel behind the stained area as you treat it. But remember to keep turning or folding the absorbent material as soon as it starts to take on some of the color of the material causing the stain, otherwise it will simply spread back into the fabric.

For the same reason, it is also important to keep turning and refolding the cloth being used to apply the solvent or cleaning fluid. To minimize the likelihood of forming a ring around the stain, try to sponge from the outer edges in toward the center rather than the other way around (this also helps to keep it from spreading). Don't wipe back and forth without refolding the cloth after one or two strokes, and don't rub hard over the stain as this may only make matters worse and could damage the fabric.

If you cannot get at the back side of the fabric - for example, on lined jackets or coats, or upholstered furniture - it's often best to use one of the paste-type cleaners such as K2R. These are sold in hardware and department stores for removing food stains and other greasy stains from carpet and fabric. After rubbing the paste gently into the stained area, allow it to dry. As the solvent dissolves the material causing the stain, the paste absorbs it and draws the stain out (it is hoped). When it dries to a powder (indicating that all the solvent has evaporated), simply brush the powder away to get rid of the stain.

To effectively attack any stain on fabric, you really have to know what caused that stain - whether the ingredients involved are greasy (in which case a solvent will be needed) or water-soluble (in which case you can often wash them out with water or a mild detergent solution).

Here are some of the most common kinds of stains and suggestions on how to get rid of them. Wherever water or detergent is recommended, be sure the fabric is washable, so test first on an inconspicuous corner. In fact, it is a good idea to test all cleaning agents mentioned on a place where any damage will not show.

The stains and cleaning ideas are:

* Blood, egg, ice cream and other organic materials: Blot with cool water or soak in cool water if practical. Then spot with warm suds from a household detergent or pre-soak solution. If the spot still remains, sponge with ammonia. If even this doesn't do it, wash in the normal manner with bleach added - but only if fabric won't be harmed by the bleach.

* Fruits, juices, wine, soft drinks, coffee, mustard: Sponge with cool water, then spot clean with warm suds. If the stain remains, spot again with vinegar. If fabric is washable, wash with bleach added. If fabric is not washable, have item dry-cleaned or sponge with dry-cleaning fluid.

* Ballpoint ink: Dab with alcohol, then immediately sponge off with clean cloth before alcohol can dry. If stain persists, try rubbing in cold cream or petroleum jelly, then washing with mild detergent and water.

* Gravy, grease, tar, mayonnaise, cosmetics, butter: Sponge with dry-cleaning fluid or a solvent such as paint thinner, but be sure to hold absorbent pad behind fabric. Keep turning both cloths frequently until stain is gone, then launder or dry clean if possible. If you can't get an absorbent pad behind fabric, use paste-type cleaner described above, or use foam-type upholstery cleaner. If stain persists, try sponging with ammonia.

* Rust: Sponge on a liquid rust remover (sold in hardware stores) but test first in inconspicuous corner. Rinse thoroughly. If this fails, try an oxalic acid solution (oxalic acid is sold in paint stores). Mix tablespoon of acid crystals in cup of hot water and sponge on. Rinse off after a few minutes, using lots of water.

* Alcoholic beverages: Rinse with cold water or spot with damp rag several times. Sponge with vinegar solution (one part vinegar to eight parts water), then rinse again. Launder or dry clean if possible. Answering the Mail Q. My outside stairs are made of pressurized wood. Where the pieces of wood are nailed together, an indentation remains and water collects there after a rain. This is causing the wood to rot in those places. What can I do to correct this problem? - M.J.K., Danbury, Conn.

A. Pressure-treated lumber should not rot just because water collects in the indentations. In fact, this type of lumber is often used underground or where it is continually in contact with moisture. I can only assume that the lumber you used must not have been properly treated. Your best bet is to replace it with properly treated wood - or complain to the dealer where you bought it.

If you want to fill in the depressions or holes on the existing wood, use an epoxy putty. However, this won't stick unless you scrape down to clean, dry wood before you apply it. Even then, the patches will obviously show, so the wood will have to be painted in order to conceal the patches and give all the wood a uniform color.

Q. Our old house has a wood bannister attached to the wall. The underside of this wood bannister feels very sticky in humid weather. What is the best way to clean this stickiness off? - Mrs. A.A., Pleasantville, N.Y.

A. You can wipe it off quite easily by using a cloth dampened with ordinary paint thinner. This solvent is flammable, so use all proper precautions. Keep changing or refolding the rag as it gets dirty, and be sure to dispose of the dirty rags outside to avoid any danger of fire.
