Magnetic Card Questions

[Sylvain Cote]

Over the years, some oxidation appears on the magnetic side of the cards which can cause reading and writing issues.
To remove that oxidation I have made small jigs for small cards (65/67/41) and long ones (71/75).
I put my card in the appropriate one and with a Staedtler Mars Plastic pencil eraser I remove the oxidation (or the pencil marking on the other side)

The jig prevents me from pinching the card which sometimes happened before.
Sylvain