All horsehair, as early as possible in the process of its manufacture, preferably before the bales are opened, or with the minimum amount of handling after the bales have been opened, shall be subjected to one of the following processes:

1. (1) Subjection to dry heat at a temperature of 200° F for 24 hours.
2. (2) Subjection to steam at 15 pounds pressure for 2 hours.
3. (3) Boiling, with the hair constantly covered with boiling water, for 3 hours.