My building uses magnetized card keys, and my officemate is always having problems with it de-magnetizing. I wanted to get her a protector or something for Christmas. What’s the search term for it? Do they even exist?
She said she’s covered with magnets all the time, which cause the problem. Her purse, buttons, etc. all have magnetic clasps.
I think it takes a very strong or fast-changing field to demagnetize a modern card, not the kind you find on a magnetic clasp.
Yes, any sort of iron (much less special alloy) will shield the strip from fields.
I think this might be part of the problem. 
Our cards are so bad, a magnet placed 1 foot away on a metal table will affect the card.
Thismight work. It is built for RFID protection, but is made from Stainless Steel, which may provide the needed protection. It seems to be costly though.
Maybe they’re not being magnetized right from the start? I’m assuming you’re magnetizing them yourselves.
Yep. Our building guy codes them with a little reader thing on his desk.
I personally have a steel (well sort of a steel fabric, made very fine wires made of soft steel which have been woven) wallet and passport holder, to protect myself when RFID based cards and passports come about.
The steel acts as a Faraday’s cage and disrupts any electromagnetic signals.