Q. We bought an older home last spring and have used the fireplace twice. Although there was no evidence of smoke seeping back into the room, there was a very pungent odor that remained after the fire was out.

With the fall season approaching, I know we will again want to build a fire even if we have a problem with lingering odors. Do you know what might cause this and what we can do? Perhaps there needs to be better drafting up the chimney. How can this be accomplished?

A. Have a professional chimney sweep inspect your system. A professional can recognize problems quickly and offer recommendations for safer, more efficient use.

In some older homes, masonry chimneys were unlined. When old bricks and mortar have deteriorated and cracked, smoke and other flue gases can easily escape into your home. This also happens when the chimney is missing portions of clay liners, or from a cracked or broken liner, loose mortar or open joints.

Another major cause of problems is poor installation of chimney liners. It may be that your chimney needs to be relined.

The buildup of creosote also is a major problem in chimneys. It forms in different fashions and textures, including a hard tarlike glaze, a crusty type that resembles corn flakes and a light fluffy powder.

When too much creosote builds up it can cause odors, but more important it can ignite quite easily. That's when a chimney fire occurs. A buildup of only one-eighth inch of creosote means it's time to clean.

Your chimney should be inspected once a year by a qualified chimney sweep. A professional will check for external deterioration and make sure that a two-inch clearance to combustibles exists on all sides of an internal chimney (an important safety rule).

If your chimney does need cleaning you can expect a complete job from a chimney sweep, which includes removing the creosote from the flue, stovepipe and clean-out door area. On a fireplace, the smoke chamber and smoke shelf also will be swept and vacuumed.

A professional chimney sweep will analyze the chimney system. This involves checking for cracks in the clay liner tiles, loose mortar and that the stove pipe is secure. The point where the chimney connector passes through a wall also will be examined; that's one of the biggest trouble spots.

There are some do-it-yourself techniques for cleaning chimneys, but I recommend a professional for safety reasons. Look for a professional chimney sweep certified by the National Chimney Sweep Guild, or one who has good client references.

Q. Is there any way to clean flat-painted wall surfaces that look dingy? I have tried vacuuming without much success. I would rather not repaint at this time if there is a way to clean the wall. I tried a wet sponge in one small area and even a small amount of moisture is going to damage the paint.

A. Use a dry sponge, available at larger housewares or hardware stores. Dry sponges are effective in cleaning nonwashable surfaces such as flat-painted walls, wallpaper and lampshades.

Turn and fold the dry sponge so that a clean part is always in contact with the surface. Do not reuse. A dry sponge should be discarded when saturated with dirt.

Send inquiries to Here's How, Copley News Service, P.O. Box 190, San Diego, Calif. 92112-0190.