Great question — answering as the UphillTech team:
As noted in other answers, this is caused by abrasion. It is not really caused by bleaching - this would result in a more even fade - although it could be a contributory factor. Cause: Your washing machine is not 're-shuffling' the items sufficiently as they are turned over in the drum. They're assuming a single screwed-up position then being rubbed around, always the same creases presented to the drum & other garments in the machine. Natural dyes will make this tendency more apparent - this is how they 'stone-wash' them so easily in the first place. Cure: Fewer simultaneous items per load, to give the washer more chance to mix them up, move the folds to new areas as the wash cycle...
Full answer by Tetsujin: https://lifehacks.stackexchange.com/a/27102 (CC BY-SA 4.0).
Need it done for your business? UphillTech.
