My two cupboards – big and deep ones, pretty much unculled for, oh, 10 years – turned out to be a clown car of neglected canned goods, the world’s largest private collection of balsamic vinegar and a lot of pasta. So much pasta.

So, on a recent afternoon, in accordance with Kondo’s organisational method, Lightner and I disgorged the contents of the larder onto the kitchen counter for sorting. Kondo would have been clapping her hands with glee (“I love mess”). The cupboards had been cluttered, sure, but functional – everything had its place, which Lightner forgivingly termed “like a personalised Dewey Decimal System.” But, then, this can of corn: How did it even get here? Nothing against canned corn, but it’s not something we use. It definitely did not “spark joy”, as per Kondo’s keep-it-or-toss-it litmus test.

But what truly does not spark joy for Lightner is the amount of food that the United States squanders while some go hungry – an estimated US$1,500-plus worth per household annually. It troubles her so much, she recently wrote a book about it: Scraps, Peels, and Stems: Recipes and Tips for Rethinking Food Waste at Home. Kondo’s dictate that anything past the expiry or best-by date should be tossed (after, of course, ceremonially thanking it) is anathema to her. “I have a grudge against date stamps,” Lightner said before we got started, “because most of them are bulls***”. Baby milk formula is the only food in the US that is legally required to bear a date; the rest are not set in stone, but rather by manufacturers who want to sell more food.

But what, exactly, is safe to keep – or, if it’s going to continue languishing unused, OK to donate to the food bank? Lightner – kind yet ruthless, funny and all-food-knowing – was here to help.

Thank God.

The amount of food was more than a little mortifying. But feeling overwhelmed, even slightly panicked, by the sheer volume of what you have accumulated is part of the Kondo process – witness the disbelieving faces of those on her Netflix series confronting the huge drifts of all their clothing piled together. “The good thing is,” Lightner said reassuringly, “you are hoarding stuff that does not really go bad.”

But I also had a special problem – call it an occupational hazard? – not reckoned with in the Kondo taxonomy. Her method involves confronting your stuff by category: clothing, books, etc. “Sentimental items” is its own classification, meant to be composed of photos and mementos, entirely separate from the kitchen. But here was an adorable tin of years-old syrup, brought back from our Canadian honeymoon and stuck away. A package of durian wafers (“Good taste! Made from real durian”), a gift from a friend who lived in Bangkok … quite a while back. A bag of Gar Gar fish cracker, featuring a funny off-brand Garfield the cat, which we had eaten a lot of on a distant trip to Myanmar.

“Having a chocolate grand piano is amazing,” Lightner said as we contemplated a miniature one in a plastic box. It came from a fancy restaurant I reviewed quite some time ago. Who can bring themself to eat a chocolate grand piano?

We ended up leaving the specific-to-me Sentimental food category for my later wrestling (with an assist from Instagram – posting photos there feels like a good way to thank the items for their service, as Kondo recommends). Lightner’s dispensation on the rest of it was invaluable – and here we go:

Dried pasta will stay in perfect condition for years. Dried egg pasta, however, may develop off flavours after 18 months, while whole-wheat pasta has oils in it that can get rancid (a good excuse for avoiding it). The bounty uncovered from my cupboards wasn’t even that old, just the product of picking up extra on sale, then stowing the packages in two different spots. Obvious not-so-professional pantry tip: store like with like, so you know how much you have, and rotate for freshness as they do at the grocery store.

Canned goods can also last almost indefinitely, if “the can isn’t doing anything creepy” like swelling, Lightner said (and she’s never actually witnessed that). Stuff that relies a lot on texture will eventually degrade, however, so keep up on your sardine-eating. Canned goods you’re not getting to are generally welcomed by the food bank (though a can of corn of very advanced age might be best off thanked, dumped in the compost and recycled).

Vinegar never goes bad. But, Lightner said, the taste of aged vinegars, like some balsamic ones, will begin to change with time – she counselled me to donate some of my unopened supply to the food bank, which I was very happy to do.

Oils eventually get rancid. Smell them – you will know.

Condiments and sauces have varying lifespans. Stuff with lots of acidity, like hot sauce, lasts a long time, but will not be the same after the colour starts to change. Stuff with lots of salt, like soy sauce, should be OK.

Sugar will always stay sweet, and salt is stalwart. Smell your flour – it should be fine unless it has absorbed other odours. The cornmeal from my cupboard had the faintest corny scent – and that is what you are looking for, according to Lightner, who suggested storing it in the fridge from now on, along with the grits, as they contain oils. Old baking powder loses its power. Old baking soda loses its fitness for baking, but can still be used to absorb odours in the fridge, unclog a sink (with vinegar) or for cleaning. Cornstarch, kept dry, will last.

Pine nuts? “They are expensive little jerks,” Lightner said, and since they are also oily, they are best kept in the fridge unless you go through them fast – same with other nuts. (Toast them in a dry pan to liven them back up.)

More foods that will last just about forever, according to Lightner: white rice, dried beans, dried lentils, honey, tea. She also says chocolate stays good, whether in piano form or not. Same with unsweetened cocoa – though any surplus unopened can of Ghirardelli might be best thanked and sent to the food bank. Know thy appetite for hot chocolate.

In the end, Kondo’ing my admittedly nightmare-level kitchen cupboards took less than three hours. We worked fast, only stopping to ponder important questions such as who had bought three different kinds of tomato soup mid-Obama era. The candles that I lit at the beginning to purify the space – a Kondoism, along with kneeling to greet the house – were less beneficial than several cups of caffeinated tea along the way (there is a reason we have so much in the cupboard).

Afterwards, Lightner said I only looked completely freaked out once. I believe this is when she said, “Is this the point where you need to breathe deeply and take a break?” She was joking, but it helped.

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