Why is milk or sandalwood paste used when making vastra from cotton?

The cotton vastra represents the Central channel (Sushumnāṇāḍi) of the Cosmic energy system (Kunḍalinī ) of the body of the embodied soul (worshipper). The seven cotton beads in the vastra are associated with the seven chakras(centres) of the Kunḍalinī system, in the body of the embodied soul. The cotton thread joining these beads is the link of the manifest Divine consciousness, providing Sattva predominant frequencies to the entire body. When the attributeless Divine consciousness in the Zero (Shūnya) manifests as per the spiritual emotion of the embodied soul towards God, its colour is white and shining. In contrast the attributeless Divine consciousness is like transparent water, but in this state it is dormant. The cotton beads and the thread joining them are the carriers of the manifest Divine consciousness in the body. Milk is used to make the constrictions in this thread because the flow of manifest Divine consciousness, is like the flow of milk. When Divine consciousness is provided to these beads, the centres (chakra) of the Kunḍalinī, in the form of beads, are activated and the embodied soul (worshipper) comes into duality. It then carries out the functions related to the physical body in the universe with the help of non-duality. Click here to read more.