With the old reel, cassette tapes, or old floppy disks, etc, there was always concern about placing them too close to a magnet, or magnetic source which could destroy the imprinted content. Large electromagnets were used to "clean" off old audio tapes.

So, is new digital storage (flash drives, SD cards, etc) subject to magnetic interference or destruction?

Can I put a magnet in my camera case without fear of ruining photos on the storage cards?