I apologize, but Im not familiar with the term "special mota" in the context of the White Cotton Janeu or the pure cotton thread Dhaga. Its possible that "mota" refers to the thickness or size of the thread. In some cases, a thicker thread may be used for the Janeu to make it more durable or visually distinct.

However, its important to note that specific terminology or variations in the materials used for the Janeu and Dhaga can vary among different regions, communities, and religious traditions within Hinduism. The customs, rituals, and preferences regarding the thread thickness or other specifications may differ.

To obtain accurate information about the specific significance of "special mota" or any other variations related to the White Cotton Janeu and Dhaga, it is recommended to consult with knowledgeable religious authorities or cultural experts who can provide insights into the particular practices and customs in your specific context.