What sort of pen is best suited to sign the back of a credit/debit card?

Question

I have 3 payment cards: 2 debit cards with different banks to spread risks, and 1 credit card. I have been using them all for months if not years by now at various places both offline and online without problems, but currently none of them are signed on the back for a very stupid reason, namely because I don't own any pens that are able to cleanly write on them.

I've tried reliable Bic pens, I've tried quality Parker pens with swappable ink cartridges, I've tried those cheap pens companies give away by the hundreds at events or markets,... Either they do not leave any ink behind when I try to write with them on the card (they do write on paper), or the ink they leave behind doesn't dry and smudges or even wipes off when I touch the card after writing. One of the cards even has a tiny bit of heavily written text left from when I first tried to sign it and failed to convincingly write my name, though by now that text has already dried.

The problem is that I don't want to keep trying pens and run the risk of damaging the card in some way. And I have NEVER had problems with these cards not being signed, because either it's a machine processing payments, or I'm paying through a payment app, or I'm paying online, or the salesperson just doesn't notice it, so I haven't seen the need to sign them yet, even though they're technically not valid unless signed.

Is there some sort of pen that's better suited for writing on the sort of material that these cards are made of?

Answer 1

I’ve found that permanent markers (sometimes called sharpies) work well. They are designed to write on a variety of material, and they dry very quickly.

Pick one with a narrow nib as some markers have fat nibs for writing large characters. Those intended for writing on CDs or even clothes & textiles should be designed to have a narrow-enough nib for signing bank cards and the like.

Answer 2

the ink they leave behind doesn't dry and smudges or even wipes off

In this situation, shortly after signing, blot the card with a piece of paper that can absorb the excess ink. That is, carefully tilt the card and paper together so that they come into contact without sliding, and apply gentle pressure for a few seconds. Then, allow the card to air out for 24 hours for additional drying before you carry it, swipe it, etc. The signature may still blur a bit over time but should remain readable.