Good news for fellow jeans lovers – apparently, you’re meant to wash them way less often than you might think.
Consumer advisory publication Which? puts the figure at about six to 10 wears before they’re due a spin in the machine, while the denim giants Levi’s say you should stick to the more “sparing” end at 10 wears, because over-washing denim can damage their shape and colour over time.
Anyone who’s owned a beloved pair of black jeans will know how true that is (my favourites have already faded to an unbecoming slate grey).
But according to cleaning expert Nancy Birwhistle, keeping your jeans jet-black without any pale streaks is as simple as adjusting a simple dial on your washing machine.
Your spin speed may be creating grey streaks on your black jeans
Speaking on This Morning, Nancy said: “When you do wash your black jeans... don’t put them on a big spin because you might get spin marks.”
Indeed, a Redditor posting to r/malefashionadvice about mysterious streaks on his black trousers found out his issue was down to spin marks.
Hotpoint says the best spin speed or rotations per minute (RPM) for denim is 800, compared to cotton’s 1,400 RPM.
Additionally, Nancy says we should turn our jeans inside-out before lobbing them in the wash, which should “always, always” be cool.
What about using vinegar?
“Before you ever wash [black jeans] for the first time, [put them in a] bowl of water... with a big, big glug of vinegar,” Nancy also advised.
However, according to Iowa State University, adding vinegar to already-dyed and processed clothes (like the kind you buy from a shop) won’t actually do much.
Calling it a “common myth,” they add that if “vinegar has been tried and it seemed to work, it is only because the free dye remnants were removed in the washing”.
“Acids help set some acid dyes in the dyeing process. While vinegar is an acid, attempting to use it after the fact, offers no ‘fixing’ protection,” they said.
Another more stable option is to choose a commercial dye fixative.
These help to form stable bonds between the fabric and the dyes that cover them, making them less likely to run or fade.