The Oil That’s Leftover

  1. According to the Tanchuma (Parshas Nasso 29), it is
    forbidden to make any use of the oil that is left over from the Chanukah
    candles because it was designated for a mitzvah. Therefore, it should be
    discarded by burning it separately. A person shouldn’t say “I am not going to
    fulfill the mitzvos of the Elders since they are not from the Torah.” G-d
    says to him, “My son, you are not permitted to say that. You should do
    everything they ordained…for I agree to all their decisions.”
  2. It is forbidden to derive benefit from the oil or the wicks
    of the Chanukah candles even if they went out after they had burned the full
    time required to fulfill the mitzvah. This prohibition applies not only to the
    one candle that is required to fulfill the mitzvah, but also to the additional
    candles we light as hidur mitzvah, for they, too, have been set apart
    to be used in the performance of the mitzvah.
  3. Oil that remains in the bottle is not prohibited even
    though the oil that was used in the menorah was taken from it.
  4. Oil that is left over from the Chanukah candles should not
    be saved to be used the following year. Since it is forbidden to derive
    benefit from it, we are afraid that it will be used, if only accidentally.
    Even if it is stored in a container which is repellent, it may not be saved.
  5. Since we benefit from the light of Shabbos candles, they
    may not be lit from oil that is left over from Chanukah candles. For the same
    reason, it is forbidden to use oil that is Orlah for Shabbos candles.
  6. If oil that is left over from the Chanukah candles mixes
    with other oil, it may be used if there are sixty parts of the permitted oil
    against one part of the forbidden oil. If there are fewer than sixty parts of
    permitted oil, there is disagreement among the poskim whether it is permitted
    to add permitted oil to the mixture. In practice, the later poskim are
    machmir
    and prohibit it.
  7. It is important when burning the oil and wicks that are
    left over from the Chanukah candles not to touch them with a knife or fork,
    for they will absorb the prohibited oil. If that happens, they can be kashered
    by hagala (immersion in boiling water). Libun is not necessary.
  8. Oil that remains from Shabbos candles after they have gone
    out may be used for any purpose. When oil remains from a yahrtzeit
    candle after it has gone out we are careful not to use it. According to the
    book of the customs of the Jewish community of Worms (Rav Yuzpa Shamash part
    two, page 249), a wax candle that has once been lit in a synagogue may be lit
    only in a synagogue, for we enhance but do not diminish kedushah. The remains
    of a yahrtzeit candle may not be used for the same reason.