It is also known as Kura Goma. These seeds are used for purifying the body. Water boiled with these seeds makes body pure. Black til is mixed in either milk/ water and then offered to Lord Shiva in the form of Abhishek. It is equivalent to doing abhishek with 'punchamrat' (a combination of 5 things). This seed is very dear to the Pitars (deceased ancestors). Shastras say that it make the person cross the Vaitarini - the sea of bad karma. One has to cross the Vaitarini to reach Vaikunta loka. During the shraadh ceremony the Kartha makes a special offering of black sesame seeds to pitars.
Besides the offering to the ancestors, black sesame seeds rolled into small balls with a boiled syrup of jaggery, are used in the shraddha meal fed to brahmins who attended the ceremony. In as much as everything in this universe is a play and pattern of vibration, the combination of black sesame and water is believed to stir up vibrations that attract the deceased ancestors to visit and partake the offerings in the ceremony in their subtle bodies.
Black sesame or kaala teel Or kala tal is part of hawansamagri, mix up in hawansamagri as homam dravya , exotice herbs. In shani,hanuman,shiva puja & hawns major samagri used is black teel.
on the day of saturday & tuesday with chameli oil black teel is offers to lord hanumanji, too remove saturn effect. Teel oil & teel is donated too removes plantery effects.