Since opening D.C. Chem-Dry® in March, David Riddle and Chuck Bleasdale have contended that the best way to convince people to use their carpet cleaning service is through free demonstrations. They are right. Not only have D.C. Chem-Dry® demonstrations landed some notable clients in only a short time - among them The Federal Building uptown and major apartment complexes - the demonstration convinced this writer of the veracity of the company's claims.

The chem-dry method produces an outstandingly clean carpet, returning it to normal softness, pile and color in less than an hour under most circumstances. Plus, the process is quiet, fast, fast drying, nontoxic, nonflammable - and comparably priced to other cleaning methods in market. My evidence?

The folks at D.C. Chem-Dry® offered to tackle the off-white carpet in my den-a surface that had not been shampooed in more than five years and contained old soft-drink and coffee spills resistant to spot cleaning, miscellaneous stains and what I called the "Black Path" of wear-and-tear in front of my couch.

Thrity minutes after D.C. Chem-Dry® had come into my apartment, the carpet looked like a rug of a different color. And it was-it no longer had the Coke of long ago, strange dots here and there or the Black path. And on some of those spots I had spent countless Saturday afternoons trying to make them disappear.

Also my carpet took only about 40 minutes to dry and the back of the piece never got wet-which is important considering this carpet isn't supported by a mat and the carpet is resting on a hardwood floor. I was impressed. The chem-dry® process-developed in California and first marketed 10 years ago on the west coast-got the carpet cleaner than anything else I'd ever used, and the cleaning process was so quick, quiet and fast-drying.

The key is the chem-dry® method. It entails spraying a patented, carbonated solution on the carpet. the solution lifts and emulsifies the dirt, and the carbonation - while helping pick up the dirt - keeps the solution from soaking through the carpet. After the carpet is sprayed, a machine with a rapidly spinning cotton pad on the bottom is moved over the wet area to absorb the solution- which is now a dirty solution from all the grime. The process does not use shampoo, which over time, stays in the carpet and itself picks up dirt.

Owner David Riddle says the chem-dry process not only cleans better but helps the carpet last longer. An example is a sandwich shop in a shopping center that had it's carpet steam - cleaned every two weeks and replaced every six months, he noted. With the chem-dry® process, the carpet initially needed cleaning three times every two weeks...then once a month for two months...then once every other month. The carpet wound up lasting three years.