I had and have some cards with embedded chips that I rarely use (a credit card, a SIM card and an Estonian E-ID card which is rather complicated and expensive to replace).

When it comes to using them, I usually discover that they don't work at first and need repeated inserting into the card reader to start work. In such cases, I noticed a matte surface on the gold plated chip contacts, so I assume the contact issue is due to oxidation. Repeated inserting or otherwise cleaning it a little would not be an issue, but in one occasion I damaged a SIM card by trying to clean it: it would only work after rubbing with a pencil eraser, but after a few such treatments it stopped working completely.

So I'd rather like to keep the chip contacts in a working fashion when the card is in long-term storage. How can I do that?

  • 2
    Gold doesn't react with oxygen, so it never rusts or corrodes. Perhaps you touched the contacts and transferred grease to them, so my hack would be never to touch the electrical contacts on a card, and only try to clean them with advised methods. Nov 15, 2021 at 8:51
  • "How can I do that?" Leave them alone. Relax. You have bee mis-informed about your reason for concern regarding storage.
    – Stan
    Nov 15, 2021 at 18:37
  • In the days of signing a payment slip, sometimes the cashier would take my card, and rub their thumb across the signature, smudging it. Perhaps a similar thing happens with your card's chip contacts: you or someone else unconsciously rubs your thumb across the contacts, applying a film of grease to them. Nov 16, 2021 at 9:48

1 Answer 1


It's not my job Lifehack

To clean a contact CHIP card (as opposed to an RFID 'contactless' tap or wave card) use a small bit of rubbing alcohol on a cotton swab to remove any oil and dirt.

That's it.

If the card does not work when inserted into a CHIP reader, the problem will almost always be with the reader NOT your cards. All the tips you find online for cleaning the CHIP are misguided as they concentrate on the wrong problem - it's their card reader contacts that need the attention.

Your card CHIP does not oxidize.

Card and CHIP readers must be cleaned regularly - especially if they are in high volume use. The contacts inside the reader get dirty and must be cleaned using a dedicated kit. You can find them online as well as provided by the credit card sales personnel. This is an extra trouble and expense that merchants are loath to do. Also, some machines are made with a limited life and must be replaced regularly. This is very expensive for the merchant. Don't forget that credit cards and their continued use is a parallel profit centre for the 'payment solutions' industry - a go-between you and your bank. Chip technology changes and fraudulent cards (the chip is glued onto another card) can mess up the card reader - requiring replacement of the reader(s) at hundreds of dollars.

One solution is to suggest to your vender/merchant that their card reader may need cleaning or replacing. The merchant will probably already be aware that people before you also have had problems with their transactions. Be understanding.

Recap: Your cards are okay.

Good luck.

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