Nudie's very own Japanese 13oz comfort stretch selvage denim will break in beautifully if you give it time to develop before first washing. If you like a more even finish earlier and more regular washing will do the trick
We recommended washing jeans inside out and wash in cold water and then line dry. The cold water wash can either be done by hand or in a front loading machine on a delicate cycle. It is worth noting that most top loading machines tend to spin the jeans too aggressively which can lead to streaks in the denim where the jeans rub against themselves.
Regardless of the washing method, air drying is essential. Air drying helps the jeans retain the custom fit you obtain through months of wear when starting with rigid denim.
Warm water washing once a jean has been worn in is perfectly acceptable but also avoid hot water or tumble drying with any denim products.