New guidelines from the CDC: You do not have to hose down everything with hot bleach for a minimum of 90 sustained minutes.

You might have one of three reactions:

1. We've turned the corner! Only 60 minutes of bleach-blasting now!

2. I never did that anyway. At most I waved a container of Purell toward a package that was delivered, much like a martini purist waving the bottle of vermouth over the brimming glass of gin.

3. That's good to know, but I'll stick to my routines, thank you. As the New Yorkers will tell you: Never pick up a can of pop without assuming a rat peed on it.

If that seems silly, it is; New Yorkers say "can of soda." Otherwise, it's true. The most important lesson I ever learned from a New Yorker boils down to ARC. It stands for "assume rat contamination."

This was back in the '80s. I was walking around New York with a friend, and we stopped to buy some Cokes. The clerk gave us straws in a paper sheaf with the top torn off. My friend, wise to the ways of Gotham, wiped off the top of the can, popped it open, and inserted the straw. Being a simple country kid from Minnesota, I asked why this was necessary.

"Rats in the storeroom," was the explanation. "You don't push the metal into the pop, because that gets rat germs in the soda, and you use a straw so your lips don't touch the can."

"Why not just do something about the rats?"

I got a look: Oh, you naive hick, thinking you can do something about the rats. This is New York, where we pride ourselves on elaborate plague-accommodating rituals. It's what makes the place special.

Mind you, New Yorkers of the era would hang on a subway pole, touch the banister going up the stairs at the station, grab the restaurant door to open it, then eat a piece of pizza with the same hand, but you get the idea. It's been 30 years, and I still rinse off the top of a can before I open it. ARC.

Anyway, this is why we will be squirting our hands with sanitizer for the rest of our lives, even though the CDC has said the obsessive sanitizing folderol isn't necessary, and soap and water's good enough. The risk of getting COVID from touching something is next to nil.

The grocery store employee who has been ritually wiping down the scanners for the past year? Turns out to be needless busywork, but it made some costumers feel safer: "He spritzed the scanner with something from a bottle. Now I can tap the screen with my knuckle with confidence." It might have been "hygiene theater," but we wanted the play to have a happy ending.

At least this means they will not have to sanitize the State Fair. I've no idea how that would have been done, anyway. Low-flying crop dusters? Firetrucks hosing down the grounds? Obviously not flamethrowers; if that stuff hit the grease accumulated over the decades, the fireball would be visible from the moon.

But you know there will be sanitizer pumps everywhere, because we've come to see these as part of the ritual of modern life. I use them every time I've touched a door. You never know: A rat could have opened that door right before me. • Twitter: @Lileks