Here's a good article about them in German:

https://davidkrenz.de/2020/11/06/zu-gut/

Pook and the Schwepnitzer sales management travelled to the international trade fairs Leipzig and Frankfurt. “We built a wall where we stacked the glasses. Look at this, breakfast! No reaction," Pook said. “I had the best connections to all major customers, at Coca Cola, for example, it was said, why should we take a glass, which does not break, we earn money with our glasses.” How much did he sell? Not a piece. “The traders understandably said who was already sawing off the branch he was sitting on.”