Bad batch of cards, or reader/writer issue?

[Sylvain Cote]

(08-06-2021 02:40 AM)rprosperi Wrote:  It works quite well, but it is VERY EASY to destroy a card, by the eraser 'catching' the card with friction and suddenly bending the card, ruining it.

I agree. I had a several hundreds cards to clean up and after destroying several cards, I came up with my card eraser jig, since then no card has been ruined this way.