How to Destroy a Memory Card

How to Destroy a Memory Card Data

Permanently destroying data on a memory card is important to protect against identity theft. In this age of cybercrime, our data is always in demand – from email phishing, hackers, and malware attacks. Apart from the internet, our data is exposed to cyber security threats when we are offline too. This is mainly due to our improper disposal of memory cards, flash drives, USB sticks, etc.. that may contain important personal data. Because personal data can lead to identity theft, it is highly imperative that we destroy our old memory cards in a secure way to put our important personal data (business data, bank account details etc..) way out of reach of hackers.You need to physically destroy the card if you want to be absolutely sure about the security of your data. This means you will need to destroy the platters of the card. Here are some good ways to destroy a memory card

Physical Destruction – Deep Scratching the Memory Card

Data contained on the card is not destroyed by simply scratching the card surface. Instead of roughing up the card surface with a superficial scratch, these scratches need to be deep and numerous to destroy the data. Simple surface scratches can easily be polished off with specialized machines. Remaining data can be retrieved. The data is stored in indentations or pits in a track running through the upper layer. The same is read while pointing a laser through the layer and measuring the change of light in the bumps and pits. Hence, we need to destroy the layer completely in order to destroy the data.

Deep scratches help destroy the memory card permanently and physically destroy the data.

Overwriting Memory Card Data

Many people are ignorant about effective deletion and permanent destruction of memory card data. Hackers and phishers take undue advantage of it. Keep in mind that the deletion of folders and files before discarding a memory card does not entirely delete the data.

Data on a memory card resides in blocks on the card. The location of the data is stored in a special directory located on the card. Deleting data only deletes the location information rather than removing the data itself. In other words, the data is not deleted, a computer or device simply does not know where the data is physically located on the memory card because the location information is marked as unused. Data is not deleted but marked by the OS as not to have been in use. Any ordinary file recovery application will find all the data easily on the memory card.

Reformatting Does Not Delete Data on Memory

Formatting is also fruitless as it comes to data protection. A quick format of data is as futile an exercise as an ordinary deletion of files or folders. A full format can stop an ordinary file recovery tool from retrieving the data, but it cannot prevent sophisticated forensic tools from retrieving the data with the use of modern magnetic measurement techniques.

Overwriting the data three or more times is a safer option as can destroy the data securely enough. The Guttmann secure algorithm method is a widely used one for it, which writes as many as 35 patterns in series over the memory card. If you are not well-versed with it, you may well go for professional help for the sake of safety and security of your precious personal data.

Demagnetization the Memory Card

No, we do not mean running a big magnet over your memory card. Data is not stored in memory cards through a magnetic process (as used in those old floppies) at all. Demagnetizing is also known as degaussing. Data is stored in the cards by altering the magnetic alignment of the platters or magnetic domains. With degaussing, these magnetic domains are made to face in the directions of the random magnetic field applied. This makes the data stored in them to be unrecoverable and unreadable. This is because there will not be enough magnetic remanence that is required to reconstruct it later in the lab. Though this method works alright, it cannot be used at home. It requires specialization and expertise. You most likely must seek professional help to do so.


To destroy storage devices like memory cards or hard drives, some organizations employ the techniques of shredding. Here, they would have machines that are like a paper shredder and can turn the hard drives or memory cards into a box of metal shards. They can also mix these shards with other shredded shards prior to disposal – thus making it impossible to reassemble it into the original physical form. However, these shredding devices are extremely expensive and are almost out of reach for an average businessperson or home user.

A home user can still do a similar thing- they can somehow stop the platters from spin. This can be achieved in many ways. One can hammer big nails through them, pummel them with a sledgehammer to turn it into an unrecoverable mess, cut the piece into half by using an angle-grinder, or dip the entire piece to a container of dilute hydrochloric acid etc..

You may use any of the techniques mentioned above to destroy a memory card. But dispose of your memory card data in a secure way and keep your data out-of-reach from hackers and unsolicited users.