The first time I noticed a shop with a Coin Laundry board, was in the Little Cuba area of Miami. I wondered why people would want to come and clean up their coins. Given, some coins are in a really bad shape, but do people really go clean them up? Are people really so particular about shiney coins? Collectors perhaps. So this was where numismatics went to get their collectables cleaned.
Then I saw another board proclaiming the same thing, and a new thought struck me. Maybe this is where you could go change your foreign money into local currency. Cuba is not too far from there. There were enough Cuban immigrants there for it to be called Little Cuba. So, This idea seemed highly plausible. Add some illegality to it and it was exciting enough for me to want to go in.
I didn’t. If I had, I would have realized much sooner that Coin Laundries were simply places where you could go do your laundry, operating the washer and dryer using coins.