Complex sentence: The herbs that the bokaye used, and likely still use, are kept secret from the buyer and to this day it is difficult to determine just how well the herbs work as a healing agent due to the bokaye not revealing the ingredients of their medicines.
Split into simpler sentences: The herbs that the bokaye used, and likely still use, are kept secret from the buyer. To this day it is difficult to determine just how well the herbs work as a healing agent due to the bokaye not revealing the ingredients of their medicines.