i don't know if it is safe or not, but you should keep it away from the magnets, just for precaution...
i have never had a problem with magnetic storage and magnets, but people say it's not that safe to keep them close...
magnets are powerful... by moving them, you alter the magnetic field, and it creates electricity!
and if you alter an electric field (by turning on and off a circuit), you create magnetism...
but i don't know if you have any dangerous electromagnetic thing at your house that can erase data from your cell phone...
if you have a floppy disk (does it still exist?), try to erase it by moving the magnets around it... and you will be afraid enough to respect the laws of phisics!
My wife gave me a cellphone case that stays closed with two magnets. Is it safe to use with a cell phone? What about with a with a micro SD card which my cell phone has?

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