Quoting Organic Sacred Ash or Vibhuti

The Anahata Organic Sacred Ash or Vibhuti is made of wood ash and burnt cow dung, procured from ‘gaushalas’ located in South India. This fragrant praying ash is chemical and colorant free, and can be used to enhance your worship experience.
https://anahataorganic.com/category/worship-essentials/worship_pooja/vibhuti/