Anti-theft security systems, which comprise a device to neutralise security tags in the check-out area of shops, can delete the magnetic stripe on a card when the card is laid on top of this neutralising device. Most shops warn customers of this by means of stickers or signs.
EC debit cards and credit cards contain a magnetic track which stores the data used to identify the card holder. If this magnetic track is damaged by strong magnetic fields, the card often becomes unusable.

Belt wallets for mobile phones, cameras, video cameras etc. with integrated card compartments are often fitted with a magnetic clasp. The magnetic field created by these clasps can damage the magnetic stripe of your cards over time.

Cases for cigarette packets usually contain a magnetic clasp. The strength of these magnets is often enough to damage the magnetic stripe.

Data can be erased from the magnetic stripe on cards by magnetic clasps found on bags (handbags, mobile phone cases, spectacle cases, laptop cases, travel bags, men's bags, wallets etc.) or on accessories such as jewellery (necklaces, bracelets, clip-on earrings etc.), and on pendants or key rings, as well as by magnetic clips used on name badges.

The headphones of mobile phones, MP3 and MP4 players, game consoles etc. generate such a strong stray magnetic field that it can destroy the magnetic stripe on a card when the two come into contact.

If you place your card on a loudspeaker or television, these could erase the data on your card, depending on how the device is shielded.

Protective cases for mobile phones, tablets or MP3 and MP4 players are also fitted with magnetic clasps that are capable of damaging (demagnetising) a card's magnetic stripe.

If a magnetic key comes into contact with a card's magnetic stripe, the key's magnetic field will erase the data from the magnetic stripe. As a result, the card can no longer be used and must be replaced, which is why you should always store your cards away from magnetic keys. Better safe than sorry!

Paperclip boxes are often magnetic, to prevent paperclips from falling out of the box. Paperclips very quickly become magnetised by the magnets in the box and can damage the magnetic stripe of your card when the two come into contact.

Ski carriers may only be an issue in winter, but they are a definite problem. These exceptionally strong magnets erase everything that comes too close to them. They have also been known to erase ski pass data, before the pass has even been used. Motorbike panniers are also equipped with very strong magnets that present a real danger of damaging magnetic stripes. This is why we do not recommend storing a card in one of these panniers without protecting the magnetic stripe.

The loudspeaker magnet in every mobile phone causes stray static magnetic fields that can damage the magnetic stripe on a card, rendering it unusable. The Vienna University of Technology has researched the effect of mobile phones on magnetic stripes and has confirmed that mobile phones can erase the data from magnetic stripes.

Extra features on mobile phones, such as MP3 or MP4 players, are turning mobiles into multi-functional devices.

As sound quality constantly improves, the stray magnetic fields created also become stronger. This, in turn, results in a growing danger that the magnetic stripe on cards gets damaged.

According to reports published in the computer magazine "c't", this magnetic catch can present a danger for magnetic stripes (and for hard drives in notebooks). The magazine article is backed up by test results and successful attempts to erase data from debit/credit cards.

Data can be erased from magnetic stripes by X-rays and magnetic resonance imaging, the latter presenting a particularly elevated risk. As far as x-rays are concerned, dental x-rays present the greatest danger, given that the patient stays fully clothed. Think about putting your card in a safe place!

Temperatures exceeding 60°C can cause deformation of your card. In the summer, the temperature inside parked cars easily reaches this limit. An unprotected card (without a SECVEL data security cover) that is exposed to direct sunlight is liable to warp within a short period of time, which causes irreversible damage.

Do not keep an unprotected card in your hip pocket or side pocket. Your card can easily get bent without a sturdy protective cover. If the magnetic track on your card does get damaged in this way, your card will only work sporadically or not at all.

Do not keep your card in the same place as loose change, keys or other hard objects unless it is protected. These can scratch your magnetic stripe very easily, rendering the card unusable.
 

Dust and grit can also collect on unprotected magnetic stripes.
If this is not removed, the magnetic stripe will get scratched every time the card is swiped through a card machine or pushed inside a conventional card protection sleeve or wallet. The card will gradually become unusable as a result. This is why you should always check that there is no dust on the magnetic stripe before you use your card.