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?