Beeswax
This term which dates back to the 1930's is commonly found in the phrase 'none of your beeswax'. It actually has nothing to do with 'wax'. It is just an intentional malapropism for business.

The following is a theory sent in by a site visitor:
I just thought I would offer some information. My U.S. History teacher (who
knows thousands of little weird facts about all colonial life) told us that
"Mind your own beeswax" was a phrase used by women in the colonial period.
Women would stand next to the fire stirring wax to make candles together.
They had to be careful not to let the wax or fire burn their huge dresses or
hair. So when someone would comment on the job another was doing, they used
the phrase "mind your own bee's wax". Now, mind you, I can鈥檛 prove it, but it
seemed legitimate to me and worth a thought :o). Anyways, love the site. (I
would love to know where the phrase "wet behind the ears" comes from though;
my friends and I were discussing it the other day) Also, maybe a bigger
"send in meanings/request an idiom" button would be helpful; it took me a
while to find your link. Thanks. 鈥揂shley

Another site visitor emailed this:
This phrase was coined many centuries ago when women used bees' wax on
their faces to smooth the skin. If they say too close to the fire, (来源：英语交友 http://friends.englishcn.com)
without the protection of a winged-bakc chair to block the heat from
their faces, the wax would start to melt. At times it would be noticed
that one of the women would be staring at another so she would say,
"mind your own beeswax." If a woman would smile with bees' wax on her face it would crack. Hence, the phrase, "to crack a smile."