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Frequently Asked Questions on Caring for Electronically Created Media in General
by Christopher Dicks, Assistant Audio and Video Conservator, Library and Archives Canada, Music Division
Can you use a dusting cloth or damp sponge to clean tapes, diskettes or CDs? How do you store these media properly? Can a scratched CD be fixed and still be played? Can a damaged tape be restored? This FAQ will answer these questions so that you can properly maintain, preserve and store your important data - whether they are texts, photographs or audio recordings.
- How do I store, handle and clean media?
- Can I restore my damaged tapes?
- What is the best way to clean CD and DVD discs?
- What can I do with a scratched CD?
How do I store, handle and clean media?
When handling media directly, it is advisable to wear thin cotton gloves. They absorb perspiration and oils from your hands. If you are not using gloves, wash your hands before handling discs or tapes. It is best to handle discs only by their edges or by their edges and inner hub. Never touch the recorded side of a magnetic tape or magnetic diskettes with your bare hands.
Keep all magnetically recorded media (audio tapes, videotapes, computer data tape, diskettes, hard drives) away from:
- magnets such as loudspeakers and fridge magnets
- tape head demagnetizers
- electromagnets such as electric drills and fans
- known sources of magnetic fields such as older computer monitors and unshielded computer speakers
Your media should be kept 7.5 cm (3 in.) away from magnetic fields. This separation should be enough to protect against most magnetic fields.
Avoid extremes in temperature. Near-freezing temperatures can cause lubricant residing within the tape to separate from the binder compound (which is the layer that holds the magnetic particles) in tapes. Extremes in temperature can also cause improper playback when a tape has not had enough time to acclimatize to the conditions it is being played in. Hot temperatures and high relative humidity can cause binder degradation in tapes, as well as warping and melting of CDs, diskettes, tapes and the tape cassette housing.
Avoid extremes in relative humidity levels. Relative humidity should ideally be around 35% and as stable as possible; although it is acceptable up to about 50%. In your home, relative humidity is more likely to be set according to your comfort level. The risk of deterioration is higher at higher humidity levels. Keep your recordings in the coolest and driest room available.
Many archives generate two copies of their digital holdings, on two different types of media (for example,
magnetic tape and CD-R). These are stored in two geographically separate locations. This reduces the concern
about the catastrophic failure of a specific type of media (for example, the tendency for the top layer of early CDs
to peel off), or about the effects of a natural (fire, flood, earthquake) or human-caused disaster. These concepts of
copying and storage may be applied on a smaller scale by non-professionals.
Can I restore my damaged tapes?
There are several ways of restoring a tape. Each method, however, should be performed by experienced professionals. Tape is made of a plastic base coated on one side with a binder compound that holds magnetic particles, which, in turn, holds the recorded signal.
Sticky-tape syndrome occurs when a tape's binder layer degrades and becomes sticky and may also begin to flake off of the base, making the tape difficult to play and leading to loss of magnetic material. This syndrome sometimes responds well to baking. Properly identified sticky tapes can benefit from exposure to elevated temperatures for several hours. Those higher temperatures reduce the tape stickiness and consolidate the binder so it does not fall apart. This treatment allows a previously unplayable tape to be played and allows the information to be copied onto a more stable format. Baking tapes is an extreme measure that irreversibly modifies the tape itself and thus the recording. The results are not always successful and are rarely permanent. This treatment is a last resort. Also, please note that a household oven cannot limit itself to the prescribed temperature, but must cycle between overheating and overcooling. Therefore, this procedure should not be attempted at home because the chance of success is low and the complete loss of the tape is likely.
Hand or machine cleaning a tape with a special tissue (Pellon) is the safest, most efficient way to clean chemical
residue and debris off a tape. Solvents should be avoided unless the tape has been submerged in water as a result
of a flood or other disaster, has been infected with mould or has been exposed to debris that is difficult to remove.
There are very specific guidelines on how and when solvents should be used. Cleaning the tape with sapphire
blades that scrape the tape surface as it passes can cause physical damage to the tape, especially if it has been
weakened or damaged. The process of bringing a tape back to playable condition can be a complicated procedure
and should be dealt with by professionals.
What is the best way to clean CD and DVD discs?
The safest way to clean a CD or DVD is using a compressed air duster. Avoid compressed solvent dusters. The second safest cleaning tool is a soft, lint-free cloth. The third safest cleaning method involves using a soft, lint-free cloth and distilled water to remove strongly attached debris. Soapy water (mild dish soap) can be used to remove greasy debris such as fingerprints. If soap is used, make another pass with clean distilled water to remove any soapy residue. If at all possible, avoid getting discs wet. Liquid solvents and detergents are not recommended. Solvents particularly may erode the disc layers.
When wiping a disc, wipe from the centre of the disc outward in a radial direction (like spokes in a bicycle wheel)
to limit the effect of any problematic scratching that may occur. A laser may be able to read "around" a radial
scratch in the disc surface, but a curved or spiral scratch could completely obscure parts of the disc if the laser's
programmed spiral movement coincides with a continuous scratch.
What can I do with a scratched CD?
A scratched CD can be sanded and polished by a specialized machine to restore the smooth, scratch-free surface. Some stores that sell used CDs own such a machine and charge for its use. Such treatments may or may not be successful.
Commercially available liquid solutions can polish out scratches. Some of these products work, while others do not. They can also cause more damage.
Other products are available to fill scratches. These products have limited effectiveness. In fact, over time the filler substance can flake off and contaminate your player. Using this type of product is not recommended.
Remember that while these methods of repairing a CD seem to work at first, they could in future cause greater
problems and "read" failures. Audio CDs can tolerate a very slight loss of readability by reconstructing similar
data or by muting briefly, but computer data and .wav files would be seriously damaged. Therefore, copy your
CD as soon as you have repaired it - if you choose to repair it.
If you need professional conservation help, please contact the Canadian Association of Professional Conservators:
CAPC
c/o Canadian Museums Association
Suite 400, 280 Metcalfe Street
Ottawa ON K2P 1R7
Tel.: (613) 567-0099
Fax: (613) 233-5438
http://www.capc-acrp.ca/index.htm
Additional Resources
For further queries on various areas of conservation, please visit:
Canadian Conservation Institute (CCI) Internet site (English and French):
http://www.cci-icc.gc.ca/
Science et patrimoine culturel, France (French only) at:
http://www.culture.fr/culture/conservation/fr/index.htm
Centre de Conservation du Québec (French and English) at:
www.ccq.mcc.gouv.qc.ca
"Conservation Online", Stanford University, USA (English only) at:
http://palimpsest.stanford.edu/bytopic/genpub/
