I have a collection of JuuL USB ecig chargers (since they are apparently disposable because you can’t buy a battery without one even though I only NEED a battery… I digress). There’s a 1/4" x 1/4" x 1/8" magnet that’s strong as hell. Dropping it down a copper pipe (if I had one) would be cool once.
Swallowing one would be a really bad idea.
Swallowing two or more, you’re looking at major surgery and possible destruction of tissue in your digestive tract.
Find a hazardous waste disposal site, or a place that accepts e-waste.
Or…if you are feeling crafty, get out the felt, the sequins, and the hot glue gun and make personalized refrigerator magnets for everyone on your Christmas list!
~VOW
If you know anyone who plays tactical or roleplaying games using miniatures, see if they want them. Building large gaming figures or squads of small figures with magnets inside to stick them together is popular right now. You can break stuff down for transport and stick them back together at the gaming table.
Neodymium magnets are good for rebuilding open frame electric motors, like the ones in some model railroad locomotives. The starting voltage is lower and the amp draw is much less.
Here’s a Bowser L1 motor with supermagnets replacing the old alcino magnet:
I used magnets from old computer hard drives to make this knife rack. First time using a router, so perhaps the very blurry pics is good at hiding my carpentry!
The back was hollowed out to within about 2mm of the front surface, leaving a solid edge. I filled the hollow with the magnets and glued them down.
I opened up my Ikea knife rack to see what kind of magnets they used. Inside were old broken hard drive magnets.
I use them to stick replaceable target faces onto my home-made backstop.
My first thought is that they should be recycled. It might not be cost-effective to do so yet, but maybe some day.
They’re generally shaped specifically for their application, e.g. powerful motors and generators, in which precise sizing and air gap tolerances are provided, so trying to use an older magnet in a new application may not work so well. Unless the application is just sticking one thing to another (like in a knife block).
I don’t understand why they don’t sell batteries without the charger. The batteries last 3 months and the chargers could last forever. The magnet has to be the most expensive part of the charger. The charging smarts are in the e-cig.
Keep saving them up. If you smoke enough and live long enough, take two bed sheets, glue thousands of them on each sheet. So each sheet repels the other. Try sleeping on the anti gravity top sheet.
Maybe you have something that a magnet would work to attach in your vehicle?
Use them to magnetize your Space Marines so the sergeant and special weapons ladz can switch out equipment between games. If you have the old metal dreadnoughts, you can counter-sink the magnets in the shoulders and the arms to make their arms swappable, too.
In another post you mentioned Quincy, IL. If you go to Tristate Games on 834 South 8th, you could see if any Warhammer players want those magnets. Or, stop by the Tangerine Bowl after 6pm on a Sunday evening, where the local gaming group meets downstairs. Ask for Kevin or Christopher. Those guys use gobs of magnets. 
They used to be great for holding important floppy discs on the fridge.
I put 8 magnets in a film canister, ran a thread between the base and lid and hung that above three magnets in a 120 deg circular pattern. It’s pretty cool. I need one of those wind up microwave turntables .
I’ve got some incredibly strong (to the point of being dangerous, they’ll damn near tear your finger off it they snap together on your hand) rare-earth magnets that I hang the trailer hitch ball and insert in the back of the truck bed when not in use. They also hang on the wall of the steel garage when not in the truck. I use a bunch of them in the Jeep for securing bottle openers, stereo remote and tools to the ceiling for easy grabbing. Got boxes of them from a high-end speaker manufacturer I used to work for. They were made just out of spec and therefor worthless to the business. They just gave them to me.
Magnets are great!
I worked on a machine that used an upside down conveyor with magnets to stack sheets of metal by pushing them off the magnets but there were too many. “You want a magnet?” Yea… I do.
They may be strong enough to attach a cargo net or tarp to the bed or sides? I have a cargo net, but it is annoying to get it hooked down well. Do you think the magnets you have would be strong enough to do such duty? Not to actually hold a load in place. But to hold the net in place at highway speed?
No doubt.