It's supposed to be. This time it took several efforts and all my strength to tear it. A sheet of newspaper placed in it will hold out just two minutes. But that is not the point. I know of only one that is not bleaching its rags.
White ones are too scarce.
It costs too much. I never sold any. Don't want to and don't expect to. I couldn't make enough to supply a demand if there were one. I've been working here nine years just to prove to myself that I have as much skill as the Guild members of the sixteenth century.