Oils and Wicks Acceptable for Chanukah Candle Lighting
It is permissible to light Chanukah candles using any type of oil and wicks. Nevertheless, the most preferable way to fulfill the Mitzvah of lighting Chanukah candles is using specifically cotton wicks and olive oil, for the flame burns the nicest using olive oil and cotton wicks. In places where olive oil is expensive, it is customary to use paraffin oil candles, commonly known as “wax candles,” which also burn very nicely and one may fulfill the Mitzvah in a beautified manner with them as well.
Olive Oil “For Lighting Only”
One may use olive oil made for lighting although it is not recommended for consumption due to health concerns.
“Floating Wicks”
Nowadays, a very common form of wicks on the market which are meant for candle lighting are cotton wicks coated with wax. Some claim that by lighting this kind of wick, one “misses out” on the preferred Mitzvah of lighting cotton wicks, since at the time when he lights the candle he is only lighting wax and he is lighting neither cotton nor olive oil. Nevertheless, Maran Harav Ovadia Yosef Shlit”a as well as Hagaon Harav Shmuel HaLevi Wosner Shlit”a write that the Halacha does not follow this opinion, for it is considered all one lighting; one in deed fulfills the Mitzvah in the preferred manner by lighting these wicks since ultimately he is lighting with cotton wicks and olive oil.
The Remaining Oil and Wicks
One should not use the oil (or wax candles) designated for lighting Chanukah candles for any other purpose, such as for eating or lighting Shabbat candles, since this oil has already been designated for the Mitzvah of lighting Chanukah candles; thus, one must not use it for any other purpose. Rather, one must burn the remaining oil on its own, with this burning serving no alternate purpose.
When we say that one may not use the leftover oil for a mundane purpose, this does not refer to the oil remaining in the bottle; rather, this refers to the oil that remains in the glass cups of the Chanukah Menorah. Only this oil should not be used for a mundane purpose or disposed of.
Some say that it is only prohibited to make use of the remaining oil when the candles were extinguished within a half-hour of being lit, for they were designated for their Mitzvah for a timespan of a half-hour. However, if the candles stayed lit for more than a half-hour and then went out, no sanctity rests on the remaining oil and one may use it for whatever he pleases. This is indeed the opinion of Maran Ha’Bet Yosef.
Nevertheless, some disagree and write that even if the candles stayed lit for more than half-an-hour, sanctity still rests on the remaining oil and wicks. Thus, one should make a “condition” before the onset of Chanukah and delineate clearly by mouth that he is not designating the oil and wicks for their Mitzvah. In this way, one may use the remaining oil and wicks for whatever he pleases according to all opinions (See Chazon Ovadia-Chanukah, page 160 and Torat Ha’Moadim- Chanukah, page 126).
Summary: The most preferable way to fulfill the Mitzvah of lighting Chanukah candles is to do so using olive oil and cotton wicks. Nevertheless, one may also use regular wax candles, especially if olive oil is very expensive.
It is proper to make a condition before Chanukah that one does not intend to designate the oil and wicks for the sake of the Mitzvah. In this way, no sanctity will rest on the remaining oil and wicks and one will be able to use them for whatever he wishes.