Magnetic money clip made from a dollar bill

Scott Amron's "Cash Money Clip" is an interesting take on money clips: a dollar bill with a steel plates stuck to it, one over a neodymium disc magnet. I'm a big fan of carrying cash in a clip (I gave up fat wallets in the back pocket and lower-back pain in favor of a small card-wallet and a cash-clip years ago) but I've never really trusted magnetic clips. It's cool to be able to stick teaspoons, small change and bits of metal to your front pocket, but your coins get stuck to 'em and you run the risk of demagnetizing your credit-cards if you absently stick your cash in the same pocket as your card-wallet.

Still, this is just too much fun -- and Amron will also sell you a kit so you can convert your own currency to a money clip (you could probably do this without the kit just by shopping around for metal and magnets, too!). Link (via Make!)

Update: Regarding demagnetizing a card, Ben Laurie sez, "Mythical, apparently. You can't hurt much, even with a rare earth magnet, apart from CRTs. I've seen this demonstrated with: a) Credit cards (hotel room keys are a low risk way of trying this yourself). b) laptops. Apparently to demag a credit card you need an oscillating magnetic source."


  1. Multiple occurrences of non-working parking garage cards and bank cards later, people in my office finally stopped storing their magnetized cards with their Blackberry: the leather pouch holding it has a magnet for keeping it shut.

    This happened to several people, first hand knowledge. I don’t think the little magnet is oscillating.

    In other words: YMMV

  2. You need either a moving magnet or a moving piece of metal, like, say, a laptop harddisk platter. I can’t find a link anymore, but some years ago the German railways had some premium seating, where the magnet to keep the tray in front of you upright was located in the tray itself, not in the front seat. People using their laptops on the train were having mysterious harddisk failures…

  3. I’ve demagnetized floppy disks by leaving them on my speakers (that was the old days) and a hotel room key by keeping it in my pocket with a cellphone. So maybe the key was not a very resilient strip but I simply won’t trust my credit cards next to anything magnetized.

  4. I worked a couple of stints at some Aluminum Reduction plants. Such plants pass low voltage DC (~5VDC) through a series of “pots” to reduce aluminum ore to aluminum. The current can be over 100,000 amps. My experience was that this was sufficient to wipe my credit cards.

    We also found that if we threw a handful of steel welding rod on the floor above the busbars carrying the current the rods would bound around on their ends and never fall over. They would all stand aligned in the same direction.

  5. the magnet has to be an AC (alternating current) magnet to do any damage.
    I had two very strong disk magnets I did some tests with and they did nothing to Videotapes or Floppies.

    hard drives have their own magnets in them, why do they even work? It defies Science!

    I am more interested in how MANY bills this thing can hold, I carry my money like this and could really use a money clip, but I like to have lots of small bills, so the wad usually has at least 20 bills in it. Carrying Six bills won’t do it for me

  6. Not sure how the Mythbusters lab test went in this case, but magnets and mag-stripe cards do not mix in my experience.

    I stay in hotels on a very regular basis and I have had to train myself not to put my room key card and my magnetic clip-on sunglasses in the same pocket.

    Any time I forget and place them in the same pocket there is a 100% history of heading back to the front desk to have the card re-issued.

    Like Ryan said, it may be that room keys have a weak strip due to the amount of time that they are re-written, but I too would never trust my mag-strip cards next to even a weak magnet, experience has shown it to be dangerous.

  7. I love this idea, I’ve been using a money “rubber band” for years. I don’t think the magnet would affect me, I put the card case in one back pocket and the money in the other.

    If I’m cash short on a day, the temptation to spend the dollar bill might be strong. Hot day, vending machine, one single dollar in my pocket, you do the math….

  8. The Mythbusters thing seemed to indicate that the real damage is done by moving the magnet over the strip, rather than just setting the magnet against the strip. One imagines that the movement of walking could create enough rubbing action between a magnetic source and the cards in your pocket to create a problem.

  9. Interesting idea. I think I’m also too chicken to try using a magnet next to my credit cards. Question though, is this a legal modification?

  10. I had some friends back in college who had some giant hard drive magnets. They usually were stuck to the metal of the circuit breaker box on the wall, and took a couple minutes of hard wrestling to pull off.

    Once, though, they put the magnets in their pockets and walked around for an hour with various forks and knives stuck to the outside of their pants. It was pretty cute, but then one of them did indeed realize that he had the magnet right next to his wallet and his credit card didn’t work the next day.

    So, even if this money clip isn’t enough to do the trick, it is possible to wipe your cards if you are toting around a fierce enough permanent magnet.

  11. @REMMELT: Actually, is is oscillating, just very slowly. You put the card in your pocket, take it out, put it in again, take the phone out, put it in again, etc. Each time you do this, it demagnetizes the card just a little bit. You don’t notice this because the card reader is sort of binary; it either can read the card or it can’t. You’d probably notice the card working intermittently for a while, then it stops working altogether when it passes a certain threshold of readability.

  12. Easy solution to wallet caused lower back pain: Switch to the front pocket.

    I prefer as thin and light as possible, but I still use a wallet over a money clip because it’s harder to tell if/how much cash is there when it’s sitting out on my desk.

  13. my good friend had a magnetic money clip and he kept his credit cards in it. everytime i went out with him his cards got refused and they’d have to put it in manually.

  14. I’ve never “got” money clips. When the money is in your pocket, your pocket holds the money together so why do you need a money clip? When you take the money out of your pocket, your hands hold it together so why do you need a money clip?

    When I want a thin profile, I just put some bills in my pocket.

  15. The problem with this will be in airports: you will have to take your clip out and pass it through the scanner in the plastic tray.

    I used to use a slim cigarette-case style metal wallet, but had the scanner problem. I switched to a Jimi because it’s slim, and plastic.

  16. To everyone who says Mythbusters proved magnets cannot demag credit cards: YouTube or it never happened.

    Certainly doesn’t mention this. Nor does a google search on “‘credit card’ mythbusters”. There’s one case of an urban legend about eel-skin wallets creating electricity to demag cards (huh?), but that’s it.

    But lets say we accept the story that MB sat a CC in front of an electromagnet and cranked its power 10 1,000 Gauss before it demagged the card. First of all, have you ever made a magnet? To actually make a piece of metal into a magnet, sitting it in front of another magnet won’t work. You have to rub the magnet against the metal dozens or hundreds of times. Putting a magnet in front of the card or even on the card will only have a temporary effect. But rub the magnet along the strip and eventually it will demagnetize. A magnetic strip on a credit or other card is a glorified piece of cassette tape. And the magnet inside a cassette deck (you’ve all taken one of these apart haven’t you?) that erases the tape to record new signal is nothing special — a neodymium magnet smaller than a pencil eraser tip.

    Furthermore… Any amount of demagnetization on your cards is going to cause you dismay. Not all card readers are created or maintained equal. Your card might still work in a new ATM but might not still work in the readers at the flour-dusted take-out-pizza window after a few weeks of sliding these two magnets in and out of your pocket/wallet multiple times a day.

  17. I have to say that from my own personal experience it IS possible to kill a magnetized card with magnets. I have a purse that closed with very strong magnets and kill half a dozen BART cards and an access key for work before I undid the stitching and pulled the magnets out. They killed the BART cards the fastest and didn’t appear to harm my CCs but once they killed my access card I said to hell with it.

    I rather suspect the demagnetization depends on the amount of time and the quality of the card, as well as how strong the magnets are.

  18. Cinemajay @10, this isn’t legal.

    From the Bureau of Engraving and Printing:
    “Defacement of currency is a violation of Title 18, Section 333 of the United States Code. Under this provision, currency defacement is generally defined as follows: Whoever mutilates, cuts, disfigures, perforates, unites or cements together, or does any other thing to any bank bill, draft, note, or other evidence of debt issued by any national banking association, Federal Reserve Bank, or Federal Reserve System, with intent to render such item(s) unfit to be reissued, shall be fined not more than $100 or imprisoned not more than six months, or both.

    Defacement of currency in such a way that it is made unfit for circulation comes under the jurisdiction of the United States Secret Service. Their address is: United States Secret Service, 1800 G Street, N. W., Washington, DC 20223.

  19. magnetic coins? are you talking about canadian or euro coins? cuz US coins are not magnetic.

  20. Credit card stripes used to have pretty low coercivity. Now most don’t. Some cheaper or older magnetic stripe hotel keys are also low coercivity.
    Most recently issued credit cards can’t be damaged (magnetically) by neodymium magnets smaller than your fist.
    I think a lot of the currency of the “magnetic clasps demagnetize credit cards,” myth comes from a kind of correlative fallacy. The card doesn’t work, you have a magnet in the pocket, therefore the magnet did it. But there are a lot of things that cause damage to magnetic stripes more easily than magnetic fields.

  21. @ Romulusnr –

    Regarding eelskin, IIRC there was a particular brand of eelskin purse that was in fashion in the late 80s. Women started noticing that their credit cards were getting ruined by it, and a popular speculation sprung up about the electromagnetic properties of eelskin, for silly but obvious reasons (think electric eels.) Then someone noticed that these purses had magnetic clasps.

    Now that I’ve written all that I get around to checking Snopes, and sure enough they beat me to it:

  22. @Romulusnr

    The episode was indeed the one about eelskin wallets. You can read the episode recap here.

    Unfortunately, I’ve had rotten luck trying to find unauthorized Mythbuster vids of any real value, not just teeny clips, but it was Season 1, Ep 3 if you’ve got access to the DVDs.

  23. How exactly does one use a magnetic money clip to stick spoons and small change to their front pocket?

    Last I checked most flatware and most American coins were not magnetic.

  24. These “World’s Thinnest Wallets” totally rock! I learned about them from KK’s Cool Tools mailing. I have the compact “European,” and it’s almost paper thin. I didn’t carry a wallet at all for nearly 10 years, until I learned about these:

    They’re made from very strong “spinnaker sail cloth,” essentially a paper-thin parachute-type material so they add virtually no extra thickness to your pocket. Highly recommended if you want super thin with the convenience of a real wallet, rather than a money clip. These are much thinnner than the magnets, in any case.

    I’ve had mine for a couple of years and it’s still pretty much intact. A few threads have started to come loose, and I’ve trimmed them off. But I expect to get another year or so at least out of mine before I replace it with another of the same.

  25. Well, first off, any magnet produces “magnetic lines of force”. If a credit card sat stationary next to a magnet, you probably wouldn’t have much of a problem. The problem comes when the credit card is moved across these lines of force. If you run a magnet back and forth across a credit card (or casette tape or floppy disk or video tape), it will “erase” it. Putting your credit card in and out of a magnetic money clip will do the same to the small strip of magnetic tape.



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