The thing that my decorating clients worry most about when they move into their newly redone apartments or homes is damage to their pristine painted walls. Although movers, installers and other workers do their best to protect all surfaces, there is invariably a ding, smudge or scratch made somewhere. I always assure clients that the painters will come back after their move is completed to touch up any marks. But what happens weeks later when their kid’s grass-stained soccer ball collides with the hallway wall and leaves a visible mark?

Typically, my clients tackle the offensive mark the way they ­tackle a scorched frying pan; they vigorously rub the spot so hard that they end up with a shiny patch on their wall that won’t go away. They’ve done what painters call burnishing; they’ve increased the gloss or sheen of the paint by rubbing the spot too much.

Burnishing is particularly easy to do on walls painted in a flat finish, which is why, although I love the chalkiness of flat paint, I suggest using it only in less trafficked areas such as living rooms and bedrooms.

When it comes to cleaning painted walls, the finish of the paint is what matters; the color doesn’t. Flat paint is the hardest to clean but the easiest to touch up. It’s also the best finish for walls that are not in great shape (when light hits glossy-finished walls, imperfections are more ­apparent than when it hits flat-finished walls).

Walls done in a high-gloss, semigloss or satin finish are by far the easiest to clean; the problem is they are hard to touch up. These finishes highlight imperfections in the walls, and when touched up, the difference in the new paint sheen and the old is often unflatteringly apparent. More ­often these finishes are used for moldings, baseboards, window and door trim, kitchen and bath walls, or any area that gets bumped, scuffed, or is prone to dirt and grease.

Eggshell is the most popular and versatile of paint finishes because it has just the slightest bit of sheen to make it an easy surface to both wash and touch up.

No matter the finish of your walls, the trick to cleaning them is to act quickly and gently, as you would any surface. The sooner you take care of a scuff or splotch, the better. Always start by vacuuming the area using the brush attachment to remove any loose dust or dirt. Dampen a clean rag or nonabrasive sponge (such as a Mr. Clean Magic Eraser), making sure to squeeze out any extra water, then dab or rub the stain very gently. If that doesn’t work, dip the cloth into water that has been mixed with a few drops of a mild dishwashing liquid. If the stain persists, try blotting a bit of the soap right onto the wall and gently rub. Once the stain is gone, gently wipe the spot with plain water to remove any soapy ­residue.

If spot-cleaning fails, you may be tempted to try a harsher cleaner, but if you do, test it in a hidden spot, such as behind a piece of art hanging on a wall. If that fails too, then you will need to touch up the spot with paint. For best results, use the paint from the original paint can and use the original mode of application; if the paint was rolled on, use a roller; if it was brushed on, use a brush.

To repair chips or scratches (or to fill holes left from picture hooks), the process is a bit more involved. I repaired a chip recently at home. Here’s how I did it:

Mayhew, a “Today” show style expert and former magazine editor, is the author of “Flip! for Decorating.”

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