To me, the takeaway is the strategy he used to start the business: "In the early 2000s, Topf began appearing outside German venues with a van, offering to pick up, wash and return the production’s clothes." Then after seeing the quality, artists/managers invited him to join tours. It's genius, simple but original and effective.
Also not surprised at the dirtiest crap ever being Slipknot's clothes. Their concerts were quite an experience. Not only is the show impressive (levitating drummers and all), but also the sheer synchronization and speed at which they play.