פירוש על שבת 45:4

Its light lasts: It does not quickly end like olive oil [does].

At first, my Master would seek sesame oil: It appears that it is referring to the Channukah lamp, and it is because of the reason that he concluded - that its light is [long-lasting]. But for the Shabbat lamp, it is obvious that olive oil is [used to perform] the choice commandment, since it is drawn more readily by the wick than all [other oils] - as it is shown in our mishnah. For they all conceded that we light with it.

Its light is clear: Clear and gives off light.