An incredible amount of effort goes into making worn and distressed denim. Here's the web site of a jeans pre-washing plant.[1] Services offered include "Crinkle Effects, Grinding/Damaging, Scrunch/ Crumple, Hand Scraping, Stone Wash, Acid Wash, Enzyme Wash, Sand Blasting Wash".

[1] http://www.mahmudgroup-bd.com/mahmud-washing-plant-limited