I searched for an answer of how to clean a N/Z strap and found pretty much what I expected. Put in the dishwasher or clothes washer.
Over a few years, I've found both of these methods to be less than ideal.
I wear my GSAR with a ZULU every workday, 12 hour days, in a ore mining/milling operation.
Between the dust, slurry, and sweat, the strap gets pretty funky in a hurry.
I tried both the posted ways without much success. The strap still held a slight odour.
I decided to try something different without resorting to chemicals.
I put the strap in glass of vinegar overnight, then just rinsed it with hot water the next morning.
It came out clean and odour free.
I've had the same strap for 7+ years, and it shows no signs of wear.
I'll keep using the vinegar.
It's time for another cleaning!