Chemical drain openers are among the most hazardous consumer products. Chemicals strong enough to dissolve clumps of grease, hair, paper and other debris can severely damage your eyes, lungs and skin. Use these products with extreme caution.

After testing chemical and mechanical drain openers, Consumer Reports' engineers advise: Resort to force first. Often, the best way to clear a drain is to push or pull on the clog.

You can buy a plunger or a plumber's snake at any hardware store. Prices start at about $2 for a plunger and at about $7 for a snake. They don't require special expertise, and you can depend on them to eliminate most clogs.

A relatively new type of product uses pressurized air or gas to push an obstruction around the bend in the drainpipe and into the clear.

Drain Power, at about $4.50, and Drano Instant Plunger, at about $5.50, are simply pressurized cans of chlorofluorocarbon gas. To use them, you stop up the sink overflow drain with rags, then push the can's cap down on the main drain opening to release a whoosh of gas.

The cans are handy, but not without drawbacks. You may have difficulty mating the caps with drain openings; a drain that's bigger than the cap will let some of the gas escape. Another important note: Gases like the ones used in these products have contributed to the depletion of the Earth's ozone layer.

Fortunately, there are alternatives you can use to blast drains clear without adding needlessly to an environmental problem.

The Pango Modelo Brevettato works on the popgun principle. You stop up the overflow drain, pump a plunger in the pistol grip, insert the "muzzle" in the drain opening, and pull the trigger. The Pango sends a powerful blast of air straight down the drain. It delivers quite a bit more force than the pressure cans do, and it doesn't pollute. The Pango costs about $20 plus shipping and is available from the Brookstone catalogue (127 Vose Farm Rd., Peterborough, N.H. 03458; Cat. No. 11111).

The Sinkmaster ($8, from M-P Corp., 8340 Lyndon Ave., Detroit, Mich. 48238) resembles a small bicycle pump. By pumping its handle, you exert both pressure and suction, moving a clog back and forth. It worked well, but fits only drains less than 1 3/8 inches in diameter.

While most drain openers are designed to move a clog down the line, the Vacuum Suction Pump No. 134841 ($10, from U.S. General, 100 Commercial St., Plainview, N.Y. 11803) exerts suction instead. It hauls the clog toward you as you pull on a handle. If the drain is stopped by an obstruction that just won't respond to forward pressure, such as a toothbrush, the Vacuum Suction Pump might help get it close enough to fish out. Unfortunately, the pump itself also will become fouled with the muck in the drain.

Other devices rely on hose power. They're available at hardware stores and resemble a canvas pastry bag. You attach one to the end of a garden hose and feed down the drain. Water pressure expands the bag, sealing it in place and pushing the clog free. The bags should work well, provided you can reach the sink with the hose.

The Drain Jet ($23) and Dr. Fixit ($8) also worked just fine. But the Drainmaster Cat. No. 50591 ($5, from U.S. General) destroyed itself after a few jobs.

To help prevent clogs, pour boiling water down your drains every week or so. Heat about a gallon, pour in half, wait a few minutes, then pour in the rest. Just be careful to pour the water directly down the drain instead of in the basin, because boiling water can crack porcelain fixtures.