Always remember that half the people you meet are dumber than average.
My brother used $2 bills as his kids’ tooth fairy money.
A big employer in my old town gave out rolls of Sacajawea dollars (among other things) as their Christmas bonus. From what I heard, quite a few of them ended up at an arcade that gave an extra play if they used a dollar coin.
I used to get $2 bills and dollar coins around Christmastime. I’d spend them to amuse myself with cashiers’ reactions. However, the last time I tried to get some, the bank wanted a $5 service charge since I had no account there so it just didn’t happen. I use a credit union, and they don’t bother with twos or dollar coins.
Every money thread eventually devolves to a discussion of two dollar bills and dollar coins.
About a year ago, I was at an estate sale and bought a bag of sewing patterns. When I inspected them to list on my Amazon resale account, I found money in some of them. It eventually added up to about $80 in crisp bills from 1984, which of course don’t look like current money, so when I spent it, the cashiers would always look at it oddly.
Had I found the money while I was there, I would have turned it into the people running the sale, but I didn’t find it until I got home, so it was mine. And I almost didn’t buy those patterns! I was glad I did.
That’s the reason I am methodically going through my deceased spouse’s things before selling anything off - sometimes you find important things.
But then, I’ve had the luxury of time in which to do this. Not everyone does, or the desire/mental ability to do this. Hence estate sales and occasional fortuitous finds for the buyers.
I think you just set forth Kayaker’s Law.
Heh, now all I need is to come up with some corollaries. 
It can also devolve into eliminating pennies.
Followed
Followed by the statement that they are officially “cents” and not “pennies”. And now primarily consist of zinc rather than copper…
The discussion must argue that cents cost more than a cent to make, and be refuted by the fact that coins simply aren’t single use items and circulate for decades.
Then people will pointlessly argue that eliminating cents will force all prices in a supermarket to be rounded to end in a zero or a five, when the only thing that needs to change is that the total purchase be rounded to the nearest five cents.
Before leaving for the Czech Republic some years ago I went to the bank & took out cash from teller, specifically $50’s & $100’s because that was much thinner wad than getting a bunch o’ $20s from the ATM . Small talk ensued about why I wanted those denominations & I said that I was going away & was to exchange them for korunas the next day. Her response was, “Oh, you’re going to Mexico”. 
Not “can”, “will”. And at least one Canadian will point out that they got rid of their pennies and dollar bills.
How exactly did “getting rid of pennies” work? We’re they declared unusable after a certain date? Did the government simply stop putting them into circulation and just let the supply dwindle to nothing?
They stopped minting Canadian pennies in 2012 and distributing them in 2013. Retailers deposited coins as they received them. They have not been demonetized and can still be deposited at a bank.
As the end approached many retailers adjusted their point-of-sale software to print the rounded amount as
$20.02
(Round down to $20.00)
If you pay cash, it’s rounded. If you use anything else - gift cards, credit, debit, etc - you pay the actual total.
Coin shortages are causing a liquidity crisis at laundromats: MSN
As the article notes, it’s not so much a shortage as a distribution problem.
For our most recent delivery from the bank at my store, where we requested $800+ in coins, the bank delivery $115 in coins and… gave us the rest in singles. Um… that’s not what we ordered. I appreciate the desire to somehow fulfill our request, but we needed coins, not singles.
The corporate office continues to get us deliveries from CoinStar itself, which is working out better. So far we’ve managed to make change for everyone who want/needs it, and some some customer continue to unload their coins on us. Yay!
So… we’re making it work. It could be worse. Just one more think in this jacked up year.
I honestly cannot remember how it came up, but one time I asked a bank teller about $1000 bills. The answer was that they would take them, but would not give them out, and, moreover, were instructed to turn them in to be destroyed.
Coins can last for decades, though. I’m sure I still have some old £1 coins somewhere, for example, and would have to deposit them at a UK bank if they turn up. But they are not in circulation, and once deposited (and you can’t do anything else with them) they would disappear as well.
I’d suggest just dropping them into the boxes at museums/churches etc next time you visit the U.K. Easy enough for them to deposit into their U.K. bank accounts