Q: What’s the best way to handle and store CDs and DVDs?

A: The answer depends on whether your disc is meant for everyday or archival use. If you’re expecting your data to survive five or 10 years, or even longer, you’ll have to take special care.

The National Institute of Standards and Technology, or NIST, recently subjected CDs and DVDs to a series of stresses. Researchers built chambers increasing heat, humidity and light to mimic aging and found the recordable DVD it tested should last 30 years if stored at 77 degrees and at 50 percent relative humidity. Tests on other types of discs are ongoing.

But conditions are often less than ideal, so count on migrating your data to a new disc long before the 30 years are up.

And more likely, if you wait that long, you won’t have the equipment capable of reading today’s file formats. Your word processor is likely to go through a dozen or more generations by then and would be incapable of reading documents stored today. So you may have to convert your music, photos, documents and other files to newer formats several times along the way.

The type of blank CD or DVD you buy for burning can matter, although there’s no easy way to tell which is best, said Fred Byers, an information technology specialist at the NIST.

Generally brand names are better, and ones made with gold are the best, although they’re more expensive and harder to find, Byers said. If you’re just burning a CD to play music in your car stereo, however, a cheap, generic disc may do just fine – you can always burn another one.

Be careful about stick-on labels. They’re not recommended if you want your disc to last more than a few years, Byers said.

You can write on the top side using CD-safe markers – generally labeled nontoxic. Avoid hard tips; felt tips are fine, unless you press down hard. And CDs are more vulnerable than DVDs to harm from writing because the layer that stores the data is closer to the top.

Handle discs using the edges or the center hole. Fingerprints will cause more trouble than scratches, although prints can be wiped off with a cotton cloth dipped in water, rubbing alcohol or special cleaning solutions sold in stores.

When storing CDs and DVDs, jewel cases are the best. If you can, keep them vertical, like books on a shelf, rather than flat, as the disc may eventually bend if your shelf does.

Paper envelopes, plastic sleeves or the spindles you buy blank discs in are theoretically OK, but they increase the risk of scratching and smudging in handling, Byers said.

Again, don’t worry about it as much if you’re just burning music for a car stereo.

CDs and DVDs are also vulnerable to light, heat and humidity – and a combination will damage a disc much more quickly than any single element, Byers said. A surefire way to lose data is to keep the disc on the dashboard of your car, parked on a treeless street on a hot, humid summer day.

Prerecorded DVDs, including movies you buy, are especially sensitive because they use aluminum, which reacts with oxygen, Byers said. Keep them in the original cases, away from the sun.

If you do have trouble reading a disc, don’t toss it right away.

It may still work on other drives, particular ones that burn discs. Perhaps you can use that machine to copy data to a new disc to play on read-only machines. (Though for movie DVDs that are copy-protected, the head of the Motion Picture Association of America recommends you simply buy a new DVD.)

Associated Press