In 1997 at The Restaurant in London, when Marco Pierre White was in the midst of his final push for Michelin perfection (which is to say, adding a full deck of five sets of red—not black—knives and forks to his restaurant’s three stars), the legendary British chef added a flourish to the service there that today seems an historical curiosity.

Cash. More specifically, clean money. When a customer paid hard currency for a meal at The Restaurant, as they did, change was delivered exclusively in crisp new banknotes and sparkling-clean coins—all fresh from the bank, never previously circulated, and unsullied.

Now, as things turned out, The Restaurant did become the first U.K. restaurant to earn that coveted perfect rating. But as Michelin inspectors never reveal their thinking, we’ll never know for sure whether clean money was a factor on their scorecards. All we can know with certainty is that if, instead of receiving change in pristine cash, one of those Michelin inspectors had been handed a portable credit card reader requesting an automated tip of 18 percent or 20 percent or even 25 percent post-tax!—the spell of perfect hospitality would have been shattered, instantly. Of course, the idea of such pushy machines, pre-programmed to prey on the innumerate, was still the stuff of waitstaff fantasy. Cash was king. You could even use it to buy a drink on an airplane. You could plunk down a twenty for a pint at the pub, assess your change privately, and decide un-goaded exactly how much to leave behind for the service. When that goes, soon, we’ll miss it. Clean and new, dirty and old—we already miss cash.