Lots of choices
There are many stories for the origin for the term 86'd.
I don't know which, if any, are the true origin, but it does provide some interesting stories. And these are only SOME of them. Do a search for 86'd and you'll find many more.
Here are 9 of them.
I'll leave number 10 for whomever know the TRUE origin of the term.
1)..."eighty-six'd" comes from the Old West. Alcohol was once allowed to be 100 proof in strength, and when a regular was known to get disorderly, he was served with spirits of a slightly lower 86 proof. Hence he was "86'd."
2)...origin of this term "eighty-sixed" was referring to the standard height of a door frame. In other words to be thrown out the door, you are 86'ed.
3)...86 or 86'd has its origins in NYC, where people committed suicide by jumping from the observation deck of The Empire State Building on the 86th floor before a safety fence was installed.
4)...in New York City back in the days when there was a saloon on every street corner and elevated trains ran along the lengths of the major avenues. One of the lines terminated at 86th Street, at which point the conductors would eject the drunks who had fallen asleep on the train. Sometimes the drunks were belligerent. The conductors took to referring to them as "86's."
5)...derived from military shorthand and referred to the phone dial (when it had letters on it). The T for Throw is on the 8 key and the O for Out is on the 6 key - hence something tossed is 86'd.
7)...originated during the Korean war. "Eighty-six" refers to the jet fighter North American F-86 Saber. Whenever an F-86 shot down a airplane during a dogfight it had been "eighty-sixed".
8)..."86" refers to the standard depth of a grave in the U.S.: 7 feet, 2 inches; thus to "eighty-six" something is to "bury it".
9)...a Johnny Hart B.C. comic strip a few years back that made an interesting observation on the name of the "abortion pill" RU-486. The folks at Roussel Uclef (the "RU") will tell you that the name/number was just one more in a series of compounds, etc. Mr. Hart however dissected "RU-486" into a darkly appropriate phrase: "Are you for 'eighty-sixing' the kid?"