Allusion על שבת 43:4

That it is Permitted to Kindle Lights From One Another, 2 Seifim: 1. We kindle one Hanukkah light from [another] Hanukkah light, and specifically kindling one from another without an intermediary, but kindling one from another through a non-sacred light is prohibited. And some permit even this, unless it is in such a way that there is concern that the non-sacred light will be extinguished before kindling the other Hanukkah light. RAMA: And we have adopted the custom to be stringent with the Hanukkah lights not to kindle even from one light to another, for its main mitzvah is only one candle, and the rest are not as much for the mitzvah. Therefore one should not kindle one from another. (Hagahot Maimoniot and Mordechai) And all this is only while they are still alight for the mitzvah, but after the time of the mitzvah has passed, it is permitted to benefit from them, [so] all the more so it is permitted to kindle from them. (Beis Yosef)

4. What remains on the eighth day of the oil necessary for the measure for kindling — he makes a bonfire for it and burns it by itself, for it has been set aside for its mitzvah. And if it becomes mixed with other oil and there is not sixty parts to nullify it, there is [an opinion] that says that one should not add to it in order to nullify it.