By MATT MAURY

It's spring cleaning time again! One of the major tasks each year is sprucing up the carpet. It can also be one of the most frustrating chores because of improper cleaning, which leaves the carpet dirty, or even damaged. Before beginning this project, take time to understand the critical elements in carpet care.

The most important thing is to vacuum regularly with a good vacuum. This means at least twice a week in the entry hall and on stairs, and weekly in the main traffic patterns of the home. When heavy soil accumulates, vacuum both north-south and east-west. A good vacuum is one with both good agitation (to lift the dirt particles into the air) and good airflow (to remove the airborne dirt). In most circumstances, an upright vacuum is more efficient in removing soil than a tank-type cleaner.

Five to 15 percent of the soil on carpeting cannot be removed by normal vacuuming because it is stuck to the carpet fibers. Maybe it is grease, maybe gum, maybe ink and maybe the dog left its mark.

For these things, extractive cleaning is necessary. Specifically, this means that some form of liquid must be applied to the fibers to release the soil and, then, the dirty liquid must be extracted. The object is to get the dirt off the carpet fibers and removed from the carpets.

Simple as this sounds, the laws of nature make the chore very complex.

When any liquid is applied to a vertical surface (and carpet fibers are vertical surfaces), gravity pulls that liquid down ... down ... down.

Because the carpet cleaning solution releases the dirt from the fibers, it is dirty liquid that is being pulled into the backing of the carpet by gravity. Removing this dirty moisture is often done with a hot-water extractor (sometimes called a "steam cleaner," although never being hot enough to produce steam).

The most efficient of the portable units can recover about 70 percent of the liquid put on the carpet. In other words, for every five gallons of liquid put on the carpet, about 3-1/2 are removed.

The remainder, which is just as dirty and just as soapy as that extracted, is held by gravity near the base of the carpet. Over the next 12 to 48 hours that moisture will evaporate, leaving the dirt particles and cleaning agents on the carpet fibers where they started - near the top.

This is why spots sometimes reappear a few days after "cleaning."

Over the years, there have been developments of "dry cleaners" using various techniques reduce the amount of liquid needed in the cleaning process.

The most recommended methods of "dry cleaning" by carpet mills are the absorbent compound techniques. These processes are effective and have no risk of carpet damage through their use. The processes require that the absorbent compounds be applied to the carpet by brush or a specifically designed machine, then, the dirty compound is vacuumed up.

Realizing that the objectives in carpet cleaning are both to remove the dirt and to minimize the amount of moisture left in the carpet, a home owner should carefully choose the proper do-it-yourself method or professional cleaner. If desiring to do-it-yourself, the best place for advice on equipment is the local carpet store or vacuum cleaner shop, NOT the local supermarket.

If choosing a professional cleaner, make sure that they have proper training. Basically, all that is being purchased is labor to do the work. Less money usually means less training and/or time spent doing the work. There are a number of good, properly insured, experienced professional cleaners from whom to choose.

A wise consumer should contact both "hot water extraction" and "dry extraction" cleaners, listening to their proposals before making a decision.