I used to say that all the time when I was middle school age. I never knew what it really meant except for stay out of my business. I actually used it quite a bit with my brother.
What does beeswax and minding it actually mean? I always thought that the wax in your ear was called beeswax because I would relate the whole saying to minding what you shouldn't be listening to.
I had looked into a couple books and "mind your beeswax" comes from.
Let us go to the trusted wikepedia
a man had a jar of beeswax and someone wanted to know what it was so he said none of your beeswax
There are a lot of theories trying to explain where the cliche "mind your beeswax" came from.
The more noted theory took place during the 18th century. During this time small pox was a very common and disfiguring disease. The ladies would fill the pockmarks on their face with beeswax, which would melt if they sat too close to the fire. If a lady was warned about her beeswax she would retort "mind your own beeswax!".
The phrase idea of minding ones own business went as far back as the 1600's. The intention of the phrase "mind your own beeswax" was to convey the same meaning as mind your own business, but soften the blow. This particular usage of the slang of "mind your own beeswax" came about around the 1930's.
As I said these are all theories. But they are very interested in trying to figure out the origin in the slang. Take the information as you may because it is "fun fact Friday!!" Enjoy your weekend.