Have you noticed that as a card grows older and has more and more insertions it just stops making contact reliably?
SDCard contact pins are made of a very thin gold and nickel plating, which unfortunately wears out quickly. Once the gold wears out, nickel is very happy to oxidize with air, creating a compound which is much less conductive.
And unlike USB, their flat surface doesn't allow for the port to automatically remove oxidation.
IPA (IsoPropyl Alcochol), is an excellent material for doing this.
The typical first-aid IPA (70% purity) is more than adequate for this, but any higher purity variants (and vodka) also work, and is effective at removing the layer of oxidation.
To clean the card it is recommend you don't drop IPA directly on the card, as tiny gaps may allow it to sink inside the card. It is instead recommended to apply trace amounts of IPA on a microfiber cloth, and rubbing the card gently with the wet part. Microfibers are only as gentle, as the pressure you apply with them. It's advised to gently rub in a circular pattern.
If you did it properly, this should only take about 5 seconds of rubbing to restore the card to reliable operation.
Do not immediately plug in the card into a device. Ensure enough time has passed for the IPA to evaporate fully. It is highly conductive and the reader along with the card may be damaged.
Keep in mind that now, as the gold layer has been worn out, the card will need more frequent cleaning. However, while it's plugged in, the area making contact should not ever oxidize. The device is likely to keep reading the card indefinetely.