Bad batch of cards, or reader/writer issue?

[rprosperi]

(08-06-2021 03:42 AM)teenix Wrote:  If you hold a card at one end with a finger and drag the eraser away from that end, and don't push toward your finger, it should never bend. Swap the card over to do the other part of the same face.

Exactly. Though this works OK for 65/67/41 cards it's not really effective for 71/75 cards, due to length. But it's 'natural' to rub the item you are cleaning (i.e. back and forth) hence the strong warning to not do it that way.