Damaged or dirty photographs are endangered heirlooms. Ideally, you have albums, digitized copies and back-ups stored in safe-deposit boxes and online. In reality, you may just treasure that smudged print or mourn the stuck-together ones -- or even have whole boxes or albums deluged by a flood, or an irreplaceable image photo-shopped by sticky fingers. For those photographs not safely tucked behind glass frames and mounted on acid-free matte, there are a few gentle cleaning methods.
Regular monochrome or color photographs, printed on photo stock from negatives, are less likely to be digitized, so a ruined print is a big deal. Fingerprints may require nothing more than gentle rubbing with a clean soft cloth;100-percent cotton is safe because the fibers are uniformly smooth. Dirty finger marks or other clingy dirt may be lightly removed with a dampened wipe, moistened with the mild emulsion used to clean eyeglass lenses. Try it on a corner before swiping it across the entire print. Photo emulsion cleaner works the same way to remove the grime that's muddying the surface of the print. You also can try a cotton ball just moistened with a small amount of rubbing alcohol, followed by a quick canned-air dry.
Your beautiful silver halide black-and-white prints with dried dirt clinging to them could be restored to clarity with a soft brushing -- but this only works for dry dirt. Silver halide photos that have suffered from immersion -- flooding and other water damage -- and are mud or sand encrusted, can be washed. FujiFilm says to put on a pair of surgical or food-handler's gloves, swish the photograph through a bath of room-temperature clean water to dislodge large chunks or patches of dirt, then soak the photo in another basin of clean water. While the photo is soaking, use your finger to lightly wipe away any surface dirt -- but don't rub hard or you could peel away the picture layer. Rinse the clean photograph in cool water and let it dry flat in a dark spot, or hang it on a line in the shade or dark.
Print your inkjet photos on photo stock and you will be able to clean them if they become smudged or soiled. Just brush them off with a soft brush to clear any dust or loose surface dirt before framing or scanning. If a photograph is fairly dirty, soak it for just 30 to 60 seconds in a basin of lukewarm water, lightly rubbing away stuck grime with the tip of your finger. "Delicate" and "quick" are the keywords here; too long a soak or too forceful a rub and you could scratch or peel away the image, or cause the ink to blur and fade. Dry washed photographs in the shade to preserve the vivid colors of the ink. Take the precaution of scanning or copying any prints before attempting a cleaning process, to have a back-up in case of problems. You can scan and fix a less-than-pristine photograph with a computer-image-manipulation program.
A valuable art print needs professional help to restore its good looks. You may lightly brush away dust or surface dirt. Even better would be a blast or two of canned air to clean the photo without touching it. The use of cleaning emulsions or more vigorous methods could irreparably damage an old photo and destroy its value. Some old prints may be cleaned with distilled water and cotton swabs, but the danger of destroying an unstable finish is not worth the risk. A professional restorer may advise you that the grime visible on the image is worth more than the cleaned-up print with no evidence of its history. If an art print is water damaged, let it dry face-up, even if it curls, to protect the print from further damage.