I have heard that there is a custom to use beeswax candles on Hannukah (at least for the shamash). Does this custom have a source? Why beeswax as opposed to other types of wax? Chabad.org notes
The most ideal way to fulfill the mitzvah is with cotton wicks in olive oil, or beeswax candles;
but I was unable to find a proper source. Can anyone shed light on this custom?