I’ll do one better:

My payment card was just a bit too wide to fit in my cellphone’s cover. The phone’s own NFC antenna is at the top - and I use it all the time - so the card had to be at the bottom of the cover to avoid triggering the phone all the time, in portrait orientation so-to-speak.

So I dissolved the card in acetone to extract the NFC chip and its antenna, then carefully reshaped one end of the antenna so it’s a bit less wide (and since I couldn’t modify the length of the wire or the number of turns in any way to avoid de-tuning the antenna too much, I sort of accordioned one side of the rectangle to accommodate the extra wire).

Then I set the new shape of the antenna permanently by carefully applying a piece of packing tape over it, flipped it over, taped over the other side to seal everything, then carefully cut around the new, ultra-thin, stubbier contactless payment “card”.

Now it fits really smartly in my cellphone cover!

I dissolved the card in acetone to extract the NFC chip and its antenna,

Wouldn’t the acetone also dissolve the insulation around the antenna wire? So when it touches itself, it shorts itself out, and – electrically speaking – you only have one turn of thicker wire?

Only one way to find out, good thing that these don’t cost any money and you can just ask for a new one.

Maybe take some cash out first to cover any payments you may need to make it it breaks in some way.