What type of oil should be used in the lamp for Deep Daan?

The Brahmavaivarta Purana prescribes pure cow ghee (go-ghrita) for lamps offered to Lord Vishnu and sesame oil (til ka tel) for lamps offered to Lord Shiva. Regular mustard oil or sesame oil is used for ancestral lamps. Cotton wicks are used for ghee lamps; red thread (kalava) wicks are traditional for Shiva lamps. The fuel type is not merely practical — it is a scriptural instruction that determines the deity and purpose of the offering.