If I had the misfortune to be required to attempt this for some reason, I would use CA glue and a very steady hand, as well as an edge to smooth the strip once applied.
This is a non-recharghable magnet paper card from the Bucharest Metro
Its just curiosity, I took the strip from a good card, sticked it to aother good one but it wasnt strong enough.
Thinking about trying it again when im in Bucharest 1 month later