Q. I have a concrete driveway that has many stains, mostly oil and rust. I tried a pressure cleaner and pure bleach. Nothing seems to help. Is there a solution for this problem?

A. This is a frequently asked question, particularly regarding stains caused by lubricants or petroleum oils that penetrate the porous concrete surface.

If spills are fresh and removed promptly, usually driveways face little danger of permanent staining. However, when oils remain on the surface for a period of time, they penetrate and become set. At this stage, they are difficult to remove.

The Portland Cement Association recommends the following methods for removing oil stains from driveways and parking lots:

* Saturate the area with mineral spirits or paint thinner. Then cover with an absorbent material such as dry portland cement, talc, cat litter, Fuller's earth, corn meal or cornstarch. Let stand overnight and sweep away the covering. Repeat if necessary.

* If an oil stain resists method A, scrub with a trisodium phosphate solution, which is available at a paint supplier.

* Soak the surface with laundry bleach.

Better yet, some commercial products now on the market do an excellent job. Most janitorial supply houses carry general concrete cleaners as well as more potent formulas such as caustic concrete cleaner for use on heavy-duty stains. Most of these come in a powdered form that is mixed with water and brushed into the concrete to remove staining. Automobile supply houses and home centers also carry concrete cleaners. Most of these are liquid cleaners applied in two parts. Follow manufacturer's directions carefully.

One product developed specifically for deep-seated oil and grease staining is Stand Off Oil & Grease Stain Remover, which is a poultice application. The stain remover combines a dry clay with a liquid additive. They are mixed at the job site to form a thick, creamy poultice paste which is applied with a trowel onto the stained portion of the concrete. Left on for 12 to 24 hours, the poultice pulls staining out of porous masonry surfaces.

The manufacturer recommends a second treatment if necessary, followed by a cleaning with its Stand Off Heavy Duty Detergent of the entire surface. For protection, Stand Off Tile & Masonry Protector can be applied, which is ideal for driveways because of its oil-resistant protection as well as water repellency. The Stand Off product line, which also includes a masonry rust-stain remover, is manufactured by ProSoCo Inc., P.O. Box 171677, Kansas City, Kan. 66117; phone 913-281-2700.

Another excellent product for the removal of concrete rust stains is Whink Rust & Iron Stain Remover, a multipurpose powder that routs rust from almost any surface except marble. It is recommended for concrete, stone and brick surfaces and is marketed by Whink Products Co., P.O. Box 230, Eldora, Iowa 50627; phone 800-247-5102.

What is the best way to clean a clogged drain? Our kitchen-sink drain is sluggish and often backs up. I am concerned about using harsh chemicals.

Drains often get clogged because of a slow buildup. The best prevention is regular cleaning with a water-activated biological cleaner as opposed to a chemical-based cleaner. Try a health-food store for a product called Earth Enzymes Drain Opener. Recommended for use once a month, this type of cleaner contains enzymes that digest organic materials.

Another natural method of keeping drains open without the use of harsh and environmentally unfriendly chemicals is to use baking soda and vinegar. On a regular basis, dump half a box of baking soda into the drain and then pour half a cup of white vinegar over it. Cover the drain tightly for a few minutes, then flush with cold water. The acidic vinegar reacts with the baking soda, creating a churning action inside the drain and eating away at the scum lodged in the pipes.

Chemical drain cleaners, in liquid or crystal form, contain powerful lyes or acids made of sodium hydroxide or sodium hypochlorite to open a blockage. However, for clogs it is best to start with a plunger.

First, fill the problem sink with water and immerse the plunger sideways to capture as little air as possible under the bell. Plug the overflow, usually found underneath the lips of sinks (above the drain on tubs), with a damp cloth so that it does not weaken your suction. Also, the plunger has to fit completely over the drain to work correctly. Move the plunger up and down a few times over the drain to build up suction, then pull it away quickly. Try a few times until either it works or it's clear that you're having no impact.

If the drain remains clogged, you can try a chemical cleaner. Be sure to follow directions carefully. If this fails, call a plumber immediately. Your sink will now be contaminated with dangerous toxins.

A few words of caution: Do not use a plunger after you have doused your sink with chemicals. The erupting fluids could be harmful.

Never use a chemical drain cleaner in a garbage disposal. It could damage the unit.

Avoid putting fat and grease into your disposal or down the sink drain. Grease coats the pipe and causes bacteria to grow.

Send e-mail to copleysd@copleynews.com or write to Here's How, Copley News Service, P.O. Box 120190, San Diego, Calif. 92112-0190. Only questions of general interest can be answered in the column.