One of the plastic wheels on our venerable plastic garden cart broke the other day, resulting in a wheel that was no longer even close to round. So, I hopped online to track down replacement wheels. Naturally, the manufacturer (De Jay or Kaz) is long out of business. A new cart costs $50-60, and then there’s the disposal issue of all of that plastic. After some hunting around, I found something on Amazon that looks like it will work: a pair of 10″ wheels by Cosco for about $30 with free shipping (might as well replace both wheels, as they are not exactly examples of robust design).
In Amazon’s sometimes-helpful “Customers who bought this also bought” display area, there were a pair of push nuts listed for about $6.
If you’ve every used a hand truck, garden cart, or just about anything else with small, lightweight wheels on it, you have almost certainly been relying upon the lowly push nut (or its close cousin, the cap nut) to keep the wheels on.
1/2″ push nut 
1/2″ cap nut
I went and looked at our old garden cart, and sure enough, that’s what it has. I was just about to add them to the order… but $6 for a pair of 5/8″ push nuts? Seriously??
I wondered if I might be able to reuse the old push nuts. It’s been years since I had to remove a push nut, and my recollection was that it involved a hacksaw (and some cursing) and yielded small bits of scrap metal and banged up knuckles.
In a fit of optimism, I consulted the oracle known as Google. Thanks to a YouTuber with the unlikely handle of American Dinosaurs Classic automobile designer (I’m not making this up), I now know how to remove a push nut without resorting to a hacksaw or other implements of destruction.
You just take an ordinary pair of household pliers and twist the nut counter-clockwise until it comes off (here’s American Dinosaur’s short video illustration). If you are tempted (as I was) to use tongue-and-groove slip-joint pliers (e.g. ChannelLock pliers), you’ll just end up spinning the push nut in place. Household pliers, on the other hand, will force you to grip the push nut at a bit of an angle, which will help work the push nut off of the axle. Easy peasy!
So, thanks to a random guy in the Mojave desert making a little YouTube video, I saved six bucks. The wheels will arrive in a few days and, with luck, will fit the garden cart with only minor modifications. I expect that the new wheels will outlast the rest of the cart, but even so it should be good for another ten years of use.